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DENTURE 
SERVICE 


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Reference  Htbrarp 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

C  Golurjibia_University  Libraries,  ,' 


http://www.archive.org/details/professionaldent01clap 


AIISH3AIMG  VinWQKW 


DEDICATION 

To  all  who  seek  to  place  denture  service  on  its 
proper  plane  in  the  esteem  of  the  profession  and 
the  public,  this  work  is  respectfully  dedicated. 


Copyrighted,   1918 

BY 

The  Dentists'  Supply  Company 
New  York 


Professional 

Denture  Service 

BY 

George  Wood  Clapp,  D.D.S. 

and 

Russell  Wilford  Tench,  D.D.S. 

With  an  introduction  by 
J.  Leon  Williams,  d.d.s. , p. r.a.s. 

1918 

Published  by 

The  Dentists'  Supply  Company 

220  West   12d  Street 
New  York 

1^  K  U  % 


CREDITS 

No  claims  are  made  for  originality  in  fundamentals. 

We  have  gladly  taken  the  best  we  have  been  able  to 
find  in  every  line  from  everyone,  have  added  to  it 
where  possible  and  have  harmonized  all  into  a 
consecutive   procedure. 

To  all  to  whom  we  are  indebted  we  give  hearty 

thanks  in  this  way  rather  than  cumber  and  confuse 

the  text  with  many  names  of  originators  of  special 

technic. 

The  Authors. 


THE  PI  EtPOSE  OF  THIS  BOOK 

is  to  present  every  important  step  in  the  technic 
of  fitting  an  edentulous  patient  with  really  pro- 
fessional dentures. 

Professional  dentures  are  distinguished  by  being 
stable  in  all  positions  of  the  mouth,  comfortable 
in  use,  efficient  in  mastication  and  natural  in 
appearance. 

The  technic  employed  is  that  taught  in  the  Labor- 
atory of  the  Research  Division  of  The  Dentists' 
Supply  Company.  It  is  being  used  with  great  satis- 
faction by  dentists  in  all  parts  oi  the  United  States. 

The  taking  of  impressions  with  compound,  the 
use  of  Williams'  methods  of  selection  and  Gysi's 
methods  of  articulation  are  taught  because  the 
writers  believe  them  to  be  sufficiently  superior  to 
other  methods  to  much  more  than  justify  the  trouble 
incident   to  their  mastery. 

Most  of  the  illustrations  are  original. 

The  imperative  method  has  been  adopted  in  the 
text  because  it  is  the  natural  method  in  teaching, 
because  it  facilitates  the  mastery  of  the  subject 
by  the  student,  and  because  it  permits  the  use 
of  fewer  words. 

As  far  as  possible  scientific  explanation  has  been 
omitted  because  the  science  has  been  incorporated 
in  its  practice. 

The   Authors. 


Table  of  Contents 


PAGE 

Introduction  by  J.  Leon  Williams,  D.D.S.,  F.R.A.S.        9 


Part  I 

Impressions  and  Bites    13 

Part  II 

Selecting  the    Size,    Form    and  Shade  in  Artificial 

Teeth    97 

Part  III 
Measuring  Habitual  Masticating  Movements 124 

Part  IV 

Arranging  the  Teeth    183 

Part  V 

Simplex  Articulator  and  Snow  Face  Bow 211 

Part  Vl 

Flasking,  Vulcanizing,  Finishing  and  Perfecting  the 

Fit    225 


Introduction 


A  Call  to  Service 

One  of  the  great  merchant  princes  of  America  recently 
said,  "The  secret  of  my  success  is  Largely  that  my  business 
is  founded  on  the  principle  that  service  shall  have  first 
consideration.  Give  the  public  the  best  possible  service 
and  the  money  returns  are  certain  to  follow." 

This  idea  of  "service  first"  is  a  comparatively  new  note 
in  the  commercial  world.  It  is  a  sound  financial  proposi- 
tion, and,  so  far  as  it  is  sincerely  carried  out,  represents 
a  great  advance  in  business  morality. 

It  is  sound  financially  because  the  wealth  of  the  world 
is  constantly  increasing,  and,  consequently,  the  standards 
of  everything  required  in  life  are  always  rising.  Those 
who  keep  abreast  of  these  rising  standards,  who  by  superior 
service  build  up  a  reputation  for  supplying  something 
Keller  than  the  average,  will  always  command  first  atten- 
tion from  those  who  want  this  superior  service  and  have 
the  money  to  pay  for  it. 

When  T  decided,  nearly  a  dozen  years  ago,  that  I  would 
devote  the  remaining  years  of  my  life  to  an  etfort  to  raise 
the  standard  of  prosthetic  dentistry,  I  saw  clearly  that 
three  fundamental  tilings  were  necessary.  The  first  and 
most  important  tiling  was  improved  forms  of  artificial 
teeth:  the  second  requisite  was  an  improved  technic  in 
all  the  processes  of  the  art  of  making  artificial  dentures; 
and  the  third  thing  that  must  be  constantly  insisted  on  was 
an  adequate  fee  to  the  dentist  for  greatly  improved  service. 

Improved  service,  the  best  possible  service  first,  and 
then  the  demand  lor  a  fee  commensurate  with  that  service. 
T  have  said  that  this  must  be  constantly  insisted  o».  and 
there  was  a  special  reason  for  this,  in  fact  two  reasons. 
The  great   majority  of  dentists  have  always  undervalued 


their  services  in  this  branch  of  practice.  They  have  not 
adequately  estimated  the  value  of  good  denture  service  to 
their  patients  and  gradually  came  to  relegate  as  much  of 
the  detail  of  this  service  as  possible  to  inferior  hands. 
JSTaturally  the  public  came  to  place  on  the  value  of  den- 
ture service  the  low  estimate  that  corresponded  with  the 
dentist's  own  estimate.  To  change  all  this  it  was  there- 
fore necessary  not  only  to  give  the  dentist  materials  and 
methods  for  a  higher  form  of  service  but  also  to  encourage 
him  in  the  effort  to  educate  his  patients  up  to  a  full  ap- 
preciation of  the  value  of  the  improved  service. 

Almost  at  the  outset  of  this  enterprise  1  insisted  that 
if  the  dentist  would  overcome  his  long  cultivated  timidity 
in  this  matter  of  fees  he  would  have  but  little  difficulty  in 
this  direction.  Americans,  especially,  I  felt  certain,  would 
be  found  as  willing  to  pay  for  value  received  in  denture 
service  as  in  other  less  important  things. 

During  the  four  years  that  Trubyte  teeth  have  been  in 
the  hands  of  dentists,  the  results  achieved  by  those  who 
have  adopted  their  use,  in  connection  with  the  greatly  im- 
proved technic  that  has  been  introduced  simultaneously, 
have  fully  justified  the  highest  anticipations  on  the  part 
of  those  responsible  for  the  introduction  of  the  higher 
standards  of  service.  Thousands  of  dentists  who  have 
adopted  these  new  methods  and  higher  standards  have 
found  such  appreciation  of  their  efforts  and  success  on 
the  part  of  their  patients  that  they  have  had  no  difficulty 
in  securing  a  very  substantial  advance  in  fees. 

And  this  experience  is  illustrated  and  confirmed  by 
numberless  instances  in  the  history  of  human  progress. 
QUALITY  OF  SERVICE  FIRST,  then  make  the  value 
of  this  service  clearly  seen  by  the  public  and  the  financial 
rewards  are  sure  to  follow. 

One  of  the  greatest  weaknesses  of  human  nature,  and 
the  one  which  most  seriously  interferes  with  success  in 
life,  is  lack  of  faith  in  oneself  and  in  others.  Whatso- 
ever a  man  thinketh,  that  he  is  and  that  can  he  do,  and 

10 


iii  the  matter  of  real  achievement  the  world  will,  generally 
speaking,  take  him  at   his  own  estimate. 

A  man's  occupation  or  calling  fills  the  larger  part  of  his 
Life  and  be  should  therefore  get  one  of  the  greatest  com- 
pensations of  life  out  of  his  calling.  And  this  greatest 
compensation  must  be  found  in  the  consciousness  that:  he  is 
rendering  the  best  service  that  he  can  to  his  fellows. 

Nothing  is  more  degrading  to  all  the  standards  of  lifo 
and  the  whole  moral  nature  of  a  man  than  the  ever-present 
consciousness  that  he  is  not  doing  his  best.  That  way  lies 
the  darkest  aspect  of  failure. 

Foremost,  among  the  works  which  The  Dentists'  Supply 
Company  has  issued  with  the  purpose  of  assisting  dentists 
in  the  improvement  of  their  technic  in  denture  service 
must  be  placed  this  little  book. 

The  authors  freely  acknowledge  that  they  have  gleaned 
many  of  the  ideas  and  methods  from  many  sources  but  I 
think  it  is  not  claiming  too  much  to  say  that  they  have 
added  some  things  of  importance  out  of  their  own  experi- 
ence and  have  so  simplified,  co-ordinated  and  illustrated 
every  step  in  the  newer  methods  of  denture  making  as  to 
produce  the  most  valuable  work  on  this  subject  that  has 
appeared. 

Not  a  single  procedure  has  been  described  that  has  not 
been  successfully  tested  and  practically  applied. 

I  often  heard  the  late  Dr.  W.  IT.  Atkinson  say  that  if  the 
bulky  dental  text  books  could  be  shorn  of  all  their  useless 
trimmings  and  superfluous  verbiage  and  so  reduced  to 
about  one-fourth  of  the  usual  size  their  usefulness  would 
be  more  than  doubled. 

This  production  seems  to  me  to  fulfill  my  old  friend's 
conception  of  the  ideal  text  book.  .May  it  be  to  those  to 
whom  they  have  dedicated  it  an  inspiration  to  establish 
Ibis  necessary  and  dillicult  form  of  dental  service  on  a 
plane  which  commands  the  respect  and  even  the  admira- 
tion of  those  who  serve  and  those  who  are  served. 

J.   LEOX  WILLIAMS. 
11 


The  Plan  of  the  Book 

The  several  steps,  from  the  examination  of  the  month 
preceding  the  taking  of  the  impression  to  the  discharge  of 
the  patient,  are  described,  as  nearly  as  possible,  in  the  or- 
der in  which  they  are  performed.  We  hope  that  dentists 
who  desire  to  follow  this  technic  may  be  able  to  open  the 
book  before  them  and  perform  the  steps  in  correct  order, 
as  they  find  them  illustrated  and  described.  This  sep- 
arates parts  of  the  technic  which  would  otherwise  be  de- 
scribed together,  but  will,  we  hope,  be  helpful  to  students. 

Modelling  compound  impressions  are  here  accepted  as. 
standard  because  we  believe  them  to  be  superior,  in  prac- 
tically all  cases,  to  other  impressions.  We  believe  that  any 
dentist  who  will  devote  to  the  mastery  of  compound  technic 
the  same  attention  that  he  must  give  to  mastering  the  prin- 
ciples of  inlay  making,  for  instance,  can  achieve  a  gratify- 
ing degree  of  success. 

Dentists  who  prefer  to  use  plaster  in  connection  with 
compound,  will  find  directions  for  doing  so  on  pages  95 
and  96. 

The  technic  of  using  the  Gysi  Adaptable  Articulator  is 
explained  in  detail,  because  an.  understanding  of  its  prin- 
ciples is  important  to  every  dentist  who  wishes  to  render 
professional  denture  service,  and  certain  portions  of  it 
may  advantageously  be  used  in  connection  with  the  Sim- 
plex Articulator. 

At  the  date  of  this  writing,  it  is  impossible  to  obtain 
Adaptable  Articulators  from  Switzerland,  but  it  is  hoped 
that  before  long  they  can  be  produced  in  this  country,  so 
that  they  may  be  placed  within  the  reach  of  all. 

The  Simplex  Articulator,  when  used  with  proper  tech- 
nic is  very  satisfactory  indeed.  The  most  desirable  technic 
for  this  articulator  is  illustrated  and  described  beginning 
on  page  211. 


12 


ERRATA 

Owing  to  unusual  condil  ions  during  preparation,  certain 
errors    in    figure    numbers    and     technical     terms    have 

occurred,  as  follows.  IT  the  reader  will  make  the  cor- 
rections on  the  pages  indicated,  annoyance  will  be 
avoided. 

Page    39,  line  13,  "D"  should  be  '"A". 

Page  43,  line  6,  should  read  "Figure  22"  instead  of 
"Figure  20"'. 

Page    73,  line  7,  "right  hand"  should  read  "left  hand". 

Page  90,  fourth  line  from  bottom  of  page.  "Figure  30" 
should  read  "Figure  31". 

Page  126,  line  is,  "Figure  124 "should read  "Figure  123". 

Page  147,  line  10,  "127"  should  read  "126". 

Page  180,  line  9,  "Figure  150  "should  read  "Figure  145". 

Page  192,  line  4.  The  sentence  beginning  "Only  the 
mesio-buccal  cusp"  etc.,  should  read:  "Only 
the  mesio-lingual  cusp  of  this  tooth  should 
touch  the  occlusal  surface  of  the  opposing  bite, 
the  disto-lingual  cusp  being  slightly  raised 
and  the  buccal  cusps  being  raised  about  three- 
quarters  of  a  millimeter  out  of  contact .  as  shown 
in  the  second  diagram  of  "A".  Figure  16*1". 

Page  194,  line  9.  The  sentence  beginning  "The  move- 
ment" etc.,  should  read  "The  movement  of 
the  teeth  on  the  working  side,  back  to  a  posi- 
tion of  rest  is  nearly  at  right  angles  to  the 
median  line". 

Page  210,  line  7.  "(b)"  refers  to  solid  line  "A-P>". 
"a"  refers  to  upper  dotted  line. 

Page  213,  last  line.        '137"  should  read  "89" 


Part  I 
Impressions  and  Bites 


Merits  of  Compound  Impressions. 

Compound,  properly  handled,  is  less  objectionable  to 
patients  than  plaster. 

The  impressions  can  be  taken  in  stages  and  the  adapta- 
tion of  both  plates  proved  before  they  are  made. 

The  guesswork  and  uncertainty  as  to  the  height  and 
form  of  the  impression  margins  common  to  other  methods 
of  impression  taking  are  avoided,  and  the  contour  and 
height  of  the  flanges  accurately  determined  by  the  actions 
of  the  muscles  upon  the  impression  material. 

To  be  successful  in  mastication,  a  denture  must  com- 
press the  soft  tissues  as  described  later  so  that  they  oppose 
to  the  thrust  of  mastication  the  same  resistance  as  the  hard 
tissue.  Only  compound  impressions  permit  proper  com- 
pression of  the  soft  tissues. 

In  mouths  presenting  a  relatively  large  proportion  of 
soft  tissue,  the  correct  use  of  compound  insures  a  greater 
degree  of  success  than  is  otherwise  obtainable. 

A  better  degree  of  success  can  be  achieved  in  taking 
lower  impressions  than  we  believe  to  be  otherwise  possible. 

The  finishing  of  the  impression  under  biting  stress  is 
very  important.  It  is  possible  only  when  compound  is 
used. 

The  use  of  compound  facilitates  the  taking  of  impres- 
sions and  bites  and  records  of  jaw  movements  at  one  sit- 
ting. The  most  exact  bite  relations  are  obtained  and  the 
bites  make  the  most  satisfactory  bases  for  taking  accurate 
records  of  jaw  movements. 

The  fact  that  a  patient  is  satisfied  with  dentures  is  no 
indication  that  they  are  the  best  obtainable.  Many 
previously  satisfied  patients  have  been  astonished  and  de- 
lighted with  dentures  made  by  the  technic  described 
herein.  It  requires  more  time  and  more  attention  to  de- 
tail than  the  impression  taking  methods  in  general  use, 
but  so  much  time  is  saved  in  the  later  stages  of  the  work, 
and  there  are  so  few  make-overs  and  the  results  are  so 
much  better  as  to  make  it  really  economical. 

14 


■  ■■••-- 


ffi  Vf»Trmaffy-r  -iii 


EXTRA   DEEP  RELIEF 
FOR   BONY    PROMINENCE 


SOFT   FLABBY    R1DGI 
SPECIAL  TECHNIC 


SEE   TECHNIC   FOR 
FRENUM    NOTCH 


AREA   USUALLY 
RELIEVED 


ANTERIOR    LIMIT 
OF   COMPRESSIBLE 
TISSUE 


HARD,    BULBOUS 
TUBEROSITY 
REQUIRES   SURGICAL 
REMOVAL 


RELIEVE   FOR   POSTERIOR 
PALATINE   CANAL 


SPINES   BEHIND   PALATINE 
CANALS    MAY    REQUIRE   RELIEF 


TISSUE   MOVEMENT   BEGINS 


RELIEVE   FOR   ANTERIOR 
PALATINE  CANAL 


HARD,  PROMINENT 
PROCESS  REQUIRES 
SURGICAL   REMOVAL 


RELIEF   FOR 
PALATINE  ARTERY 
SEE  FIGURE  62 


THIN.   HARD   MUCOSA 
REQUIRES   HIGH 
FLANGE  AND  CLOSE 
ADAPTATION 


LIGAMENTOUS 
ATTACHMENTS 
SEE   FIGURE  23 


RELIEVE  FOR   POSTERIOR 
PALATINE  CANAL 


EXTREME    LENGTH   PLATE. 
FLABBY   RIDGE 


Fig.  1 


This  illustration  summarizes  many  of  the  conditions 
in  the  mouth  which  affect  the  procedure  of  impression 
taking,  and  serves  to  emphasize  certain  steps  in  technic. 
It  is  placed  here  so  that  when  the  technic  of  impression 
taking'  is  understood,  it  may  serve  as  an  easily  accessible 
reminder  of  certain  important  details. 


15 


Classification  of  Tissue  Conditions  in 
Edentulous  Mouths. 

It  will  be  found  useful  to  classify  the  conditions  of  the 
tissues  in  edentulous  mouths  as  a  means  of  determining 
the  procedure  most  likely  to  yield  satisfactory  results.  Mr. 
Supplee's  classification,  which  follows,  will  be  found  a 
valuable  aid  in  the  selection  of  an  impression  material,  in 
teaching  and  in  the  interchange  of  thought  among  workers. 

It  also  helps  to  understand  why  dentists  who  have  suc- 
cessfully made  dentures  from  plaster  impressions  cannot 
succeed  for  the  same  patient  4  or  5  years  later,  although 
they  use  the  same  materials  and  technic.  Mouths  in 
Classes  1  and  2  tend  to  pass  into  the  conditions  in  Classes 
3  and  4,  especially  if  the  artificial  dentures  are  not  well 
articulated,  or  when  the  patient  is  compelled  to  masticate 
on  the  incisors. 

UPPERS. 

Class  1.  Firm  ridges  covered  with  a  uniform  layer 
of  slightly  yielding  membrane.  Buccal  and  labial  attach- 
ments connected  high  on  border  of  ridge. 

If  plaster  impressions  are  to  be  satisfactory  anywhere, 
it  will  be  in  this  Class  and  Class  2.  Muscle  trimmed 
plaster  impressions  may  be  made  by  the  technic  described 
on  pages  95  and  96. 

Class  2.  Firm  ridges  and  vault  covered  with  tensely 
drawn  membrane.  Very  small  area  of  soft  tissue  over 
the  rear  third  of  the  hard  palate  on  either  side  of  the 
median  line.  Buccal  and  labial  attachments  connected 
close  to  the  crest  of  the  ridge  and  very  definite  in  move- 
ment. 

Class  3.  Firm  ridges.  Soft  area  in  the  vault,  par- 
ticularly over  the  rear  third  of  the  hard  palate  on  either 
side  of  the  median  line.  The  buccal  and  labial  attach- 
ments are  connected  to  the  ridge  areas  of  movable  soft 
tissue  overlying  the  buccal  and  labial  surfaces. 

16 


Small  bony  prominences  are  often  hidden  under  ilic 
soft  membrane  and  cannot  be  detected  and  properly  lo 
cated  withoul  pressure  by  ;i  ball-end  instrument. 

Successful  dentures  for  mouths  in  Classes  3  and  4 
arc  almost  Impossible  when  plaster  is  used  for  impres- 
sions because  localized  compression  of  the  soft  tissue-  is 
essential.  They  require  the  use  of  compound  and  the 
technic  described  in  the  following  pages. 

('lass  1.  High  or  low  vault.  Soft  ridges  or  tuberosities. 
Buccal  and  labial  attachments  cither  high  or  low.  Vault 
either  hard  or  varying  in  density. 

LOWERS. 

Class  1.   The  prominent  ridge  that  is  hard  all  over. 

Class  2.  The  flat,  hard  ridge  with  prominent  muscles 
whose  hases  of  attachment  are  at  least  V4  inch  from  the 
crest   of  the  ridge  in  the  molar  region. 

Class  3.  The  flat  or  high  ridge  where  the  muscular 
attachments  are  movable  to  the  crest  of  the  ridge,  par- 
ticularly in  the  molar  region.  (In  many  cases  this  type 
has  indirect  attachment  to  the  top  of  the  ridge  through 
areas  of  movable  soft  tissue.) 

Class  4.  The  flexible  or  soft  ridge.  Muscular  attach- 
ments either  direct  or  indirect  through  soft  tissue. 

CLASS     1. 

(supplee) 


LOWER   ANTERIOR  LOWER  POSTERIOR 

EXPLANATION    OF   MARKS UPPER. 

1.    Muscular  attachments  connected  high  on  labial  bor 

der  of  ridge. 

-.   Vault  covered  with  a  uniform  layer  of  membrane. 

3.   Slight  soft  areas  in  rear  third  of  vault. 

17 


EXPLANATION  OF  MARKS  —  LOWER. 

4-6.  Muscular  attachments  connected  low  on  labial  and 
lingual  border  of  the  ridge. 

5.  Uniform  layer  of  membrane  over  a  prominent  ridge. 
4a-5a-6a.   Same  condition  in  molar  region. 

CLASS     2. 

(supplee) 


LOWER  ANTERIOR 


LOWER  POSTERIOR 


1. 


EXPLANATION    OF   MARKS UPPER. 

Muscular  attachments  of  labial  border  connected  near 


the  crest  of  ridge. 

2.  Vault  covered  with  thin,  tensely  drawn  membrane. 

3.  Bony  prominence  often  present  in  this  class  of  Case. 

4.  Small  area  of  soft  membrane  in  rear  third  vault. 


EXPLANATION   OF   MARKS LOWER. 

4-6.  Labial  and  lingual  attachments  connected  close  to 
crest  of  ridge. 

4a-6a.   Same  condition  in  molar  region. 
5-5 a.   Thin  tense  membrane  covering  ridge. 

CLASS     3 

(supplee) 


LOWER  ANTERIOR  LOWER  POSTERIOR 

EXPLANATION    OF   MARKS UPPER. 

1.   Muscular    attachment    connected    to    ridge    through 
areas  of  soft  tissue  (la). 

18 


2.  Comparatively  deep  urea  of  sofl  membrane  covering 
the  vault. 

B.  A  small  pronounced  bony  prominence  La  often  hid- 
den under  the  sofl  membrane,  thai  cannol  be  detected  with- 
out pressure. 

'.'>.  Varying  depth  of  movable  sofl  tissue  under  the  mem- 
brane covering  the  rear  third  of  the  vault. 

EXPLANATION    OF    MARKS LOWER. 

l-i;.    Buccal  and   lingual  attachments  connected  to  the 
ridge  through  an  area  of  soft  movable  membrane  (5). 
4;H>;t.    Same  condition  in  the  molar  region. 

CLASS      4. 

(5JPPLEE) 


LOWER  ANTERIOR 


LOWER  POSTERIOR 


EXPLANATION    OF   MARKS UPPER. 

The  predominant  characteristics  of  a  Class  4  case  is  a 
soft  ridge  in  front  (  3a  >,  flexible  tuberosities,  or  both. 

1.  Labial  attachments  that  may  he  either  high  or  low, 
but  connected  to  soft  ridge  (3a). 

2.  The  membrane  may  be  thin,  heavy,  or  varying  in 
density. 

3.  Movable  soft  tissue  in  rear  third  of  vault  that  may 
be  small  and  shallow  or  large  and  deep. 

li.    A  bony  prominence  that  is  often  evident  in  this  class 
of  case. 

EXPLANATION   OF   MARKS  —  LOWER. 

4-6.    Buccal   and  lingual    attachment    connected   to  soft 
ridge  (7)  through  the  movable  membrane  (5). 

4a-6a.   The  same  thing  in  the  molar  ridge. 

The  sofl  ridge  I  7-7a  |  as  a  general  rule  is  thin,  ribbon- 
like,  and  very  flexible. 

19 


Fig.   2. 

Locating  Compressible  Palatal  Tissues. 

The  posterior  margin  of  the  plate  is  to  be  located  on  the 
soft  tissues  which  overlie  the  posterior  area  of  the  hard 
palate.  These  are  compressible  but  do  not  move  much. 
The  ball  end  of  an  instrument,  pressed  against  these 
tissues,  can  be  felt  and  seen  to  compress  them.  Watch  the 
soft  palate  and  with  a  soft  indelible  pencil  mark  the  palate 
14  inch  back  of  where  movement  in  these  tissues  begins 
when  the  patient  says  "Ah". 

The  tray  should  extend  to  this  point  to  confine  and  sup- 
port the  compound  and  facilitate  proper  adaptation. 


20 


Fis 


Determining  Length  of  Tray. 

The  point  "A"  shows  where  movement  of  the  soft  tis- 
sue begins  when  the  patient  says  "Ah".  Trim  the  tray 
to  reach  to  the  line  "B",  ]  t  inch  behind  the  point  "A". 
For  patients  who  gag  easily,  it  may  he  necessary  to  stop 
the  tray  at  or  y$  inch  in  front  of  "A". 

impression  1  rays  of  thin  material  are  much  more 
easily  trimmed  and  adapted  than  thick  trays. 

Apply  cold  cream  or  white  vaseline  to  the  corners  of 
the  patient's  mouth  to  protect  them  during  impression 
taking. 


Fig.  4. 

Trimming  Upper  Impression  Trays. 

"A"  shows  a  thin  aluminum  perforated  impression 
tray  in  the  form  in  which  it  is  received  from  the  maker. 

"B"  shows  the  same  tray  with  the  flange  cut  away  in 
the  incisor  and  bicuspid  region  to  facilitate  adapting  and 
trimming  the  compound.  When  this  tray  is  in  the  mouth, 
it  reaches  back  to  the  line  "B"  in  Figure  3. 


22 


BSH 

^■j^  --*»^ 

PV 

li  1 

I  w 

•►  i  *  ■ 

\) ^  3*—    "^ 

B 

K- 

?pt-   -V 

[r^ 

\l 



— *^ 

Fig.  5. 

A  Heater  for  Impression  Compound. 

Compound  cannot  be  properly  manipulated  for  impres- 
sions and  bites  unless  the  heat  by  which  it  is  softened 
can  be  controlled  so  as  to  develop  the  required  working 
qualities.  We  have  found  the  heater  here  shown  satisfac- 
tory. Have  the  water  in  the  vessel  about  3  inches  deep. 
Keep  the  top  of  the  heating  ring  ]  L>  inch  below  the  surface 
and  the  bulb  of  the  thermometer  1  inch  below  the  surface. 

Immerse  three  sheets  oL:  compound  in  the  water  to 
soften  for  impression  work  while  the  tray  is  being  shaped. 

The  temperature  of  the  water  should  be  about  150°  F., 
never  above  L60°  F.  With  the  water  at  this  temperature 
learn  to  soften  compound  to  the  bending  stage,  the  mould- 
ing stage  and  the  flowing  stage. 


23 


Fig.  C. 


Perfecting  the  Fit  of  the  Tray,  Part  I. 

It  is  often  impossible  to  properly  adapt  the  tray  to  the 
tuberosities  by  sight.  Soften  two  small  rolls  of  compound 
in  water  at  150°  F.  and  place  on  the  tray  as  shown.  Carry 
the  tray  into  the  mouth  and  press  carefully  upward  until 
the  posterior  margin  of  the  tray  is  about  %  inch  from  the 
vault  and  parallel  to  it,  and  the  anterior  margin  is  about 
ys  inch  below  the  ridge  in  front,  as  here  shown.  The 
front  margin  of  the  tray  should  extend  forward  to  a  point 
directly  below  the  most  prominent  part  of  the  ridge.  Re- 
move the  tray  from  the  mouth  and  chill  the  compound. 

The  compound  blocks  are  called  "Adjustment  blocks." 


24 


Perfecting  the  Fit  of  the  Tray,  Part  II. 

The  medial]  line  of  the  soft  palate  is  usually  clearly  pink 
or  white  and  its  location  easily  seen.  Place  the  tray  carry- 
ing the  adjustment  blocks  in  the  mouth.  When  it  is  in 
position,  make  a  plainly  visible  line,  with  a  sharp  exca- 
vator, on  the  lingua]  surface  of  the  tray  so  that  it  continues 
the  median  line  of  the  soft  palate  forward,  as  shown  by  the 
black  lino  on  the  tray,  in- this  illustration.  Remove  the 
tray  and  deepen  the  line. 

When  carrying  the  heel  of  the  tray  upward,  in  begin- 
ning  to  take  the  impression,  this  line  on  the  tray  should 
be  directly  below  the  median  line  of  the  soft  palate. 

25 


Fig.  8. 


Perfecting  the  Fit  or  the  Tray,  Part  III. 

The  thickness  of  the  adjustment  blocks  shows  whether 
the  tray  properly  fits  the  tissues.  At  the  point  "1"  in  "A" 
the  tray  was  too  close  to  the  tissues,  as  is  shown  by  the 
compound  margin  being  less  than  %  inch  thick.  At 
point  a2"  in  "A"  the  compound  margin  is  more  than  y8 
inch  thick,  showing  that  the  tray  was  too  far  from  the 
tissues. 

Cut  off  the  compound  projecting  through  the  perfora- 
tion in  the  vault  of  the  tray.  Remove  the  adjustment 
blocks  and  trim  the  flanges  which  are  more  than  Yg  inch 

26 


Perfecting  the  Fit  or  the  Tray,  Part  III. 
Continued. 

thick,  until  they  are  uniformly  !y  inch  thick  as  shown 
in  "B". 

Reseat  each  adjustment  block  in  the  tray.  Grasp  tray 
and  block  firmly  between  thumb  and  lingers  at  "D"  and 
burnish  the  flange  of  the  tray  against  the  block.  When- 
ever the  compound  flange  is  too  thin,  as  at  "1"  in  "A", 
insert  a  knife  between  block  and  tray  and  bend  the  tray 
outward.  When  the  tray  is  properly  lined,  remove  the 
adjustment  blocks. 

Tf  the  tray  is  improperly  fitted,  there  may  lie  too  much 
compound  in  the  impression  at  the  tuberosities.  This  may 
interfere  with  bite  taking  or  the  free  movement  of 
the  mandible  and  the  taking  of  correct  Gysi  records.  In 
some  cases  the  mandible  moves  so  close  to  one  or  both  tuber- 
osities thai  proper  records  can  be  taken  only  by  the  method 
described  on  page   125. 


27 


Fig.   10. 

Preparing  the  Upper  Tray  eor  the  Attach- 
ment or  the  Compound. 

Grasp  the  dry  tray  with  pliers  and  warm  it  in  the  flame. 
Heat  the  end  of  a  stick  of  compound  in  the  outer  zone 
of  the  flame  until  it  sputters  and  paint  the  palatal  surface 
of  the  tray,  as  shown.  Compound  applied  in  this  manner 
will  adhere  more  firmly  than  if  applied  to  a  cold  tray  and 
will  afford  a  better  attachment  for  the  impression  com- 
pound. 


28 


Fig.  11. 

Preparing  the  Upper  Tray  for  the  Attach- 

MKXT  OF  THE  BlTE  RlM. 

At  this  time  the  under  surface  of  the  tray  may  be  pre- 
pared for  the  attachmenl  of  the  hire  rim  in  such  manner 
;i^  in  prevent  it  coming  loose  from  the  tray  during  the  sub- 
sequent manipulation.  Heal  ;i  stick  of  compound  in  the 
outer  zone  of  ;i  bunsen  flame  until  it  begins  to  sputter 
and  paint  the  lingual  surface  of  the  ridge  portion  of  the 
tray  ;i<  shown  here. 


29 


Fig.  12. 

A  Test  for  Quantity. 

With  the  glass  spatula,  raise  from  the  bottom  of  the 
heater,  a  small  mass  of  compound  and  form  into  a  sheet 
3/16  inch  thick  and  of  approximately  the  area  of  the  tray, 
with  enough  to  turn  up  for  the  marginal  flanges  of  required 
height  as  here  shown.  It  is  usually  better  to  have  a  slight 
surplus  than  not  enough.  For  patients  who  gag  easily,  less 
than  enough  may  be  used  in  the  region  of  the  heel,  and 
deficiencies  in  the  impression  filled  up  by  additions  from  a 
tracing  stick  later.  Shape  this  test  sheet  as  here  shown. 
Remove  it  and  dip  in  hot  water  and  knead  with  the  hand 
till  it  is  of  nearly  flowing  consistency  throughout  the  mass. 

30 


Fig.  13. 

Attaching  the  Impression  Compound. 

The  tray  and  the  compound  already  painted  upon  it 
should  be  dried  with  a  towel  or  bibulous  paper. 

Shape  the  mass  of  softened  compound  as  shown  in  this 
picture  and  beat  the  point  of  it  in  the  bunsen  flame  until 
it  sputters.  Press  it  quickly  upon  the  compound  already 
mi  the  palatal  surface  of  the  tray  and  mould  it  to 
approximately  the  shape  of  the  finished  impression. 


31 


Fig.  14. 

Shaping  the  Compound  in  the  Tray. 

Shape  the  compound  so  that  the  mass  in  the  center  of 
the  vault  will  be  high  but  the  posterior  margin  of  the  tray 
will  be  free  from  compound.  As  this  mass  touches  the 
palate,  it  flows  to  the  rear.  Form  a  depression  for  the 
alveolar  ridge  and  shape  marginal  flanges,  which  will  go 
between  the  ridge  and  the  cheeks.  These  flanges  should 
be  about  3/10  inch  thick.  This  shaping  should  be 
practiced  until  one  acquires  skill  to  finish  it  while  the 
compound  still  moulds  easily. 


32 


Fig.  15. 

Chilling  the  Compound  Next  to  Tray. 

The  tray  and  about  |s  inch  of  the  compound  next  to  it 
are  immersed  in  cold  water  for  about  5  seconds.  This 
hardens  the  lower  pari  of  the  compound,  which  assists  in 
adapting  the  softer  compound  to  the  tissues,  and  prevents 
forcing  the  tray  through  the  compound  and  into  contact 
with  the  tissues.  Tip  the  tray  to  right  and  lefl  so  that  the 
buccal  surface  of  the  flanges  may  he  slight lv  chilled  also. 


33 


Fig.  16. 


Softening  Palatal  Surface  of  Compound. 

Use  an  alcohol  lamp  and  a  mouth  blowpipe.  Direct  a 
small  blowpipe  flame  against  the  compound  in  the  center 
of  the  vault  and  soften  it  until  the  surface  is  smooth  and 
of  a  flowing  consistency.  The  compound  in  the  center 
should  be  heated  to  a  greater  depth  than  that  portion  of 
the  material  which  is  to  come  in  contact  with  the  crest  and 
sides  of  the  alveolar  ridge.  When  the  compound  in  the 
center  has  been  sufficiently  warmed,  direct  the  flame  into 
the  depression  for  the  ridge.  Heat  until  the  surface  there 
is  smooth.  Do  not  heat  the  ridge  surface  of  the  flanges 
enough  to  cause  them  to  fold  over  on  themselves.  Do  not 
allow  the  flame  to  rest  in  one  place.     Keep  it  moving. 

34 


/ 


Fig.  17. 


Chilling  the  Right  Hand  Marginal  Flange. 

Touch  the  side  of  the  right  hand  marginal  flange  of 
tho  tray  and  compound  to  cold  water  or  ice-water,  but  do 
not  allow  the  cold  water  to  work  over  onto  the  surface 
heated  with  the  blowpipe.  The  object  is  to  stiffen  the 
compound  flange  so  that  ir  will  not  fold  over  upon  itself 
when  introduced  into  the  mouth.  Proper  technic  will 
make  the  bucca 
inner  surface  soft  and  flowing 


urface  of  the  flange  hard  and  leave  tho 


35 


Fig.  18. 

Equalizing  Surface  Temperature  of 
Compound. 

The  hardening  of  the  buccal  surface  of  the  marginal 
flange  should  have  occupied  not  more  than  three  seconds 
and  the  surface  of  the  rest  of  the  compound  should  still 
be  too  hot  to  permit  introducing  into  the  mouth  without 
burning.  Invert  the  tray  and  compound  over  the  hot 
water  as  shown  here,  dip  the  blowpipe  heated  surface  in- 
to the  hot  water  and  immediately  withdraw  it  with  a 
jerking  motion.  This  operation  must  be  very  quickly  per- 
formed, or  the  hard  layer  next  to  the  tray  and  the  flanges 
will  be  unduly  softened. 


36 


Fig.  10. 

Introducing  Compound  for  Upper  Impression. 

Part  I. 

Support  the  tray  on  the  middle  finger,  guiding  it  side- 
ways with  the  thumh  and  forefinger.  Hold  the  right  side 
of  the  impression  toward  the  patient.  Carry  the  right  side 
of  the  impression  into  the  month  and  against  the  right 
corner  of  the  month.  Distend  the  left  side  of  the  mouth 
with  the  left  forefinger.  Tfotate  the  tray  quickly  so  that 
the  left  heel  passes  the  left  corner  of  mouth.  The  left 
forefinger  protects  the  left  flange  from  being  bent  by  lip 
pressure. 


37 


Fig.  20. 


Introducing  Compound  for  Upper  Impression, 

Part  II. 

With  the  finger  of  the  left  hand,  pull  the  cheek  out- 
ward  to  protect  the  marginal  flange  on  left  side.  At  the 
same  time,  pull  the  traj  and  compound  a  little  to  the 
right  and  drop  the  left  flange.  The  right  buccal  flange 
may  have  been  bent  slightly  and  this  procedure  assists  in 
passing  it  upward  between  the  ridge  and  the  cheek.  Move 
the  tray  upward  and  a  little  to  the  left  to  offset  the 
previous  pull  to  the  right  and  the  tilting.  Hold  the  tray 
in  this  position  with  the  compound  lightly  in  contact  with 
the  tissues,  and  make  sure  that  the  front  and  back  portions 
of  the  tray  bear  the  relation  to  the  ridge  shown  in  Figures 
6  and  7.  !STow  press  the  tray  about  half-way  home  and 
hold  it  in  this  position  during  the  manipulation  described 
for  Figure  21. 

38 


Carrying  the  Compound  Flanges  IIkjtt. 

W'iih  the  Left   index  finger  press  the  lefl   buccal  flange 

upward  and  inward  between  cheek  and  ridge,  from  tuber- 
osity to  cuspid  as  shown  at  ".V". 

Withdraw  the  left  index  finger  with  a  sliding  motion 
upward  and  forward  until  it  is  in  the  position  shown  at 
■•J)".  This  stretches  the  lip  and  check  muscles  and  places 
the  labial  and  buccal  soft  tissues  in  a  favorable  position 
for  taking  the  impression.  Tat  the  compound  from  cuspid 
to  cuspid  lightly  upward  and  toward  the  ridge. 

Substitute  the  left  middle  finger  for  the  right  middle 
finger  supporting  the  tray  as  shown  at  "C". 

Manipulate  the  right  buccal  flange  with  the  right  index 
finger  as  the  left  buccal  flange  was  manipulated  in  "D". 

Return  the  index  and  middle  fingers  to  the  position 
shown  at  "C"  and  press  the  tray  home. 

Ivclease  the  right  hand  and  hold  the  tray  firmly  in  po- 
sition with  the  left.  With  the  index  finger  of  the  free 
hand,  make  pressure  on  the  outside  of  the  cheeks  opposito 
the  vertical  center  of  the  compound  flange  and  force  the 
compound  gently  upward  and  inward  against  the  ridge. 

('hill  the  compound  by  means  of  \U  inch  cotton  rolls 
wrung  out  of  ice-water,  or  with  low  pressure  air.  Do  not 
remove  the  impression  until  it  is  absolutely  hard. 

'The  impression  will  now  usually  show  marked  suction. 

Extreme  caution  should  be  employed  in  removing  tho 
impression.  Many  impressions  are  spoiled  in  removal  by 
faulty  technic.  Insert  an  index  linger  between  the  cold 
compound  flange  and  the  cheek  and  lift  the  tissues  some- 
what as  shown  at  "A"  to  admit  air  between  the  ridge  ami 
flange.  Work  impression  gently  downward  and  forward 
in  such  way  as  to  drop  the  lefl  heel  ami  side  until  the  air 
works  freely  under  the  impression,  when   it  will   release. 

If  the  patienl  can  close  the  lips  and  distend  tin1  cheeks 
with  air,  the  impression  will  be  dislodged  with  a  minimum 
danger  of  distortion.  Immerse  impression  in  cold  water 
and  allow  to  remain  1  -  minute. 

■:.\) 


Fig.  21. 


40 


Fig.  22. 

Trimming  the  Surplus  from  Upper  Impression. 

The  manipulation  described  lias  turned  over  the  sur- 
plus material  shown  at  "A",  leaving  the  impression  upon 
which  the  final  muscle  trimming  will  be  done  in  the  area 
within  the  dotted  line.  With  a  sharp  knife  cut  away  the 
surplus  material  in  such  way  as  to  leave  the  margin  of  the 
flange  not  less  than  1/g  inch  thick,  which  is  less  liable  to 
be  distorted  by  the  rapid  absorption  of  heat  than  a  thin- 
ner flange.  It  will  be  safer  for  a  beginner  to  leave  the 
flange  a  little  more  than  y$  inch  thick. 

As  a  thick  flange  can  be  less  rapidly  muscle  trimmed 
than  a  thin  one,  one  or  two  more  heatings  may  be  neces- 
sary, but  tli is  is  compensated  for  by  the  reduced  danger  of 
flange  distortion. 

The  impression,  after  the  removal  of  the  surplus,  is 
shown  at  "B", 


41 


mmm 


Fis 


Trimming  the  Impression  for  Length. 

Trim  the  tray  and  impression  in  normal  cases,  to  reach 
back  to  the  point  where  movement  of  the  soft  tissues  be- 
gins, when  the  patient  says  "Ah".  To  do  this,  trace  a  line 
at  this  point  on  the  soft  palate  and  transfer  it  to  the  im- 
pression. The  ends  of  this  line  should  rest  on  the  com- 
pressible but  non-moving  tissue  in  the  depression  behind 
each  tuberosity,  and  the  line  should  cross  the  vault  where 
movement  in  the  tissues  commences. 

Koll  a  swab  of  cotton  tightly  on  an  instrument,  and 
with  the  application  of  firm  pressure,  wipe  the  tissues  of 
the  posterior  part  of  the  vault  free  from  mucin. 

42 


Moisten  the  point  of  a  soft  indelible  pencil  in  water 
;mk1  draw  this  line.  Slightly  moisten  the  impression,  place 
ii  in  the  month,  press  it  firmly  againsl  the  vault,  and 
rotate  it  a  little,  if  possible,  thereby  transferring  the  lino 
from  the  tissues  to  the  impression  as  shown  a1  "B"  in  Fig 
ure  20.  Too  much  moisture  on  the  impression  will  make 
the  line  indefinite. 

liemove  th<1  impression  and  trim  the  tray  and  impression 
to  the  line,  cutting  so  as  to  hold  the  tray  against  the 
compound. 

[f  there  is  cloubt  as  to  where  the  line  should  rest,  it  is 
better  to  leave  the  impression  a  little  too  long  and  trim  the 
plate  it'  irritation  makes  it  necessary. 

In  some  mouths  the  area  of  compressible  hut  non-mov- 
ing tissue  behind  the  tuberosities  is  very  narrow  because 
of  unusual  ligamentous  attachments.  To  determine  tbo 
character  of  these  attachments,  have  the  patient  open  the 
mouth  as  wide  as  possible  and  watch  the  tissues.  Make 
a  dot  on  each  side  where  movement  commences  when  the 
ligament  becomes  tense.  If  the  denture  is  finished  to  rest 
upon  the  point  of  attachment  of  this  ligament,  it  will  be 
pulled  loose  whenever  the  mandible  is  dropped,  by  the 
action  of  the  ligament. 

In  cases  where  the  mouth  presents  a  soft,  flabby  ridge 
in  front,  tbe  plates  must  be  made  longer  than  in  normal 
cases,  to  prevent  breaking  the  valve  fit  in  the  back  by  the 
unavoidable  excessive  movement  of  the  plate  in  speech, 
swallowing  and  mastication.  In  extreme  cases  ir  may  be 
necessary  to  extend  the  plates  *  \  inch  beyond  the  point 
where  movement  commences  when  the  patient  says  "Ah*'. 

[f  the  impression  does  not  show  suction,  add  black  wax 
as  shown  in  Figure  64.  If  the  addition  of  the  wax  docs 
not  produce  the  desired  result  repeal  the  impression  tech- 
nic,  beginning  at    Figure  10. 

In  very  difficult  cases  a  beginner  may  find  it  accessary 
to  follow  the  alternative  technic  under  the  title  "Com- 
pound-Plaster 1  mpressions." 

43 


Fig.  24. 


Attaching  the  Upper  Bite  Rim,  Part  I. 

Take  from  the  hot  water  enough  compound  to  form  a 
roll  ^2  inch  in  diameter  and  3  or  4  inches  long.  Heat  in 
the  flame,  until  it  sputters,  enough  of  one  side  to  reach 
from  the  first  molar  to  the  median  line.  Attach  the 
heated  portion  to  the  previously  prepared  ridge  area  of 
the  tray  so  that  the  end  of  the  roll  will  he  about  where 
the  distal  side  of  the  first  molar  is  expected  to  come. 

If  this  bite  rim  is  left  too  long,  it  may  interfere  with 
equalizing  the  bite  pressure  or  the  free  movement  of  the 
mandible  and  the  taking  of  correct  records  of  jaw  move- 
ments. 


44 


Fit 


Attaching  the  Uppee  Bite  Rim,  Pakt  II. 

The  tray  is  here  shown  hold  in  the  left  hand,  with  the 
unattached  portion  of  the  roll  forming  the  bite  rim  in  the 
right  hand.  Direct  a  bunsen  flame  against  that  portion 
of  the  hito  rim  which  will  be  attached  to  the  tray,  taking 
care  not  to  heat  the  tray  or  the  impression.  When  the 
compound  sputters,  withdraw  from  contact  with  the  flame 
and  press  it  against  the  tray.  This  heating  should  com- 
plete the  attachment  of  the  rim  to  the  tray. 


45 


Fig.  26. 

Attaching  the  Upper  Bite  Rim,  Part  III. 

While  the  bite  rim  is  still  soft,  cut  off  the  surplus  ma- 
terial about  where  the  distal  side  of  the  first  molar  will 
come.  Invert  the  impression  as  shown,  and  immerse  tray 
and  impression  in  cold  water  up  to  the  point  of  the  at- 
tachment of  the  bite  rim  to  the  tray.  This  is  to  prevent 
the  heat  in  the  bite  rim  softening  the  impression. 

The  bite  rim  is  trimmed  shorter  than  has  been  custom- 
ary, to  bring  the  stress  in  bite  taking  forward  of  the  up- 
ward incline  on  the  rear  portions  of  the  lower  ridge. 


46 


What  the  Occlusal  Plane  Is. 

It  is  :m  arbitrary  plane  which  has  generally  been  ac- 
cepted because  it   is   useful   in  arranging  artificial  teeth. 

This  plane  is  generally  parallel  to  a  line  on  the  outside  of 
the  cheek  from  the  upper  margin  of  the  external  auditory 
meatus  to  the  lowest  point  of  the  wing  of  the  nose.  If,  in 
edentulous  cases,  the  occlusal  surface  of  the  hire  rims  be 
made  parallel  to  it.  and  on  a  level  slightly  below  the  upper 
lip  at  rest,  the  most  advantageous  position  for  the  arrange- 
ment of  the  teevh  will  he  established. 

The  practical  value  of  the  occlusal  plane  is  about  as 
follows : 

It  estahlishes  a  generally  accepted  starting  point  for 
the  arrangement  of  artificial  teeth. 

It  is  of  value  in  mounting  models  in  articulators, 
whether  or  not  the  face  bow  is  used. 

Its  use  facilitates  the  achievement  of  pleasing  esthetic 
effects. 

The  cusps  of  Trubyte  teeth  can  be  set  against  this 
plane,  as  will  be  shown,  to  easily  and  quickly  establish 
approximately  correct  compensating  and  lateral  curves. 


47 


Fis.  27 


Establishing  the  Plane  of  Occlusion, 
Part  I. 

Dip  the  bite  rim  in  hot  water  until  it  is  plastic,  which 
requires,  usually,  about  10  seconds.  Put  the  impression 
with  bite  rim  attached  into  the  mouth.  Mould  the  bite 
rim  in  the  labial  and  buccal  regions  to  about  the  contour 
the  teeth  are  to  take. 

Make  sure  that  when  the  moulding  of  the  bite  rim  is 
completed  it  is  directly  above  the  lower  ridge.  This  will 
prove  to  be  important  in  later  stages  of  the  work. 


48 


Fig.  2S. 

Establishing  the  Plane  of  Occlusion, 

Part  II. 

When  the  contour  of  the  bite  rim  has  been  satisfactorily 
established,  press  the  occlusal  surface  of  the  bite  rim  in  the 
fnmt  of  the  mouth  upward  with  the  finger,  as  shown,  push- 
ing the  surplus  toward  the  center  of  the  mouth,  until. 
when  the  patient  raises  the  lip  as  in  smiling,  the  bite  rim  is 
exposed  about  as  the  teeth  arc  to  be. 

Press  the  sides  of  the  occlusal  surface  of  the  bite  rim 
upward  in  the  same  manner  until  they  are  approximately 
parallel  to  the  occlusal  plane.  "When  the  patient  raises  the 
lip,  it  should  he  possible  to  see  more  of  the  compound  in  the 
incisor  region  than  in  the  posterior  region. 

49 


Fig.  29. 


The  Plane  of  Occlusion,  Front  View. 

The  horizontal  position  of  the  occlusal  plane,  when  seen 
from  the  "front,  should  be  parallel  to  a  line  through  the 
pupils  of  the  eyes. 

After  the  occlusal  surface  of  the  upper  bite  rim  has  been 
made  approximately  parallel  with  the  occlusal  plane,  lay 
a  ruler  across  the  anterior  section,  as  here  shown,  and  test 
the  parallelism  with  the  line  through  the  eyes. 

Tf  one  side  of  the  bite  rim  is  too  deep,  whittle  it  until 
the  plane  is  established. 

In  cases  where  the  lip  is  habitually  raised  unevenly, 
giving  the  mouth  a  crooked  appearance,  the  best  esthetic 
results  will  be  obtained  by  setting  the  edges  of  the  teeth 
pretty  closely  to  the  plane  here  described. 

50 


Fiff.  30. 


The  Plane  oe  Occlusion,  Side  View. 

Tn  edentulous  cases,  establish  the  antero-posterior  level 
of  the  occlusal  plane  by  drawing  a  line  on  the  face  from 
the  upper  margin  of  the  external  auditory  meatus  to  the 
lowest  pari  of  the  wing  of  the  nose,  by  means  of  a  ruler,  a 
Strip  of  celluloid  or  a  cord.  Parallel  the  occlusal  surface 
of  the  bite  rim  to  this  line  and  test  the  parallelism  by  hold- 
ing a  ruler  againsl  the  occlusal  surface  of  the  bite  rim  as 
shown  above,  and  observing  the  projecting  portion.  Cut 
away  the  occlusal  surface  or  add  to  it  at  the  heel  as  may 
he  necessary  to  establish  the  plane. 

In  the  preceding  illustration  and  this,  the  ruler  is  shown 
supported  in  position,  with  the  operator  out  of  view,  for 
photographic  reasons. 

51 


Fig.  31. 
CORRECTING   ERRORS   IN   BlTE   RlM   DEPTH, 

Part  I. 

The  edges  of  the  upper  centrals  are  usually  exposed 
when  the  lips  are  slightly  parted.  The  upper  lip  is  usually 
raised,  in  smiling,  to  the  necks  of  the  upper  centrals.  Trim 
the  upper  bite  rim  so  that  it  is  exposed  from  1/16  to  1/8  of 
an  inch  when  the  lips  are  slightly  parted. 

Stand  several  feet  in  front  of  the  patient.  Have  her 
smile.  Decide  whether  the  depth  of  rim  exposed  is  greater 
than  the  length  of  the  teeth  suitable  for  the  face.  If  it  is, 
trace  a  line  on  the  labial  surface,  as  here  shown,  and  re- 
establish the  plane  of  occlusion  at  this  level. 

52 


Fig.  .°.2. 

Correcting  Errors  in  Bite  Rim  Depth, 
Part  II. 

If  it  is  necessary  to  trim  the  surface  of  the  lute  rim, 
pass  the  surface  to  be  trimmed  through  the  side  of  the 
bunsen  flame  and  heal  it  to  a  depth  of  not  more  than  1/16 
inch.  Cut  with  a  cold,  very  sharp  knife.  It'  much  is  to 
he  cut  away,  make  several  shallow  heatings  rather  than  one 
deep  heal  ing. 

The  patient  is  here  shown  with  the  Into  rim  trimmed  to 
the  proper  vertical  depth  and  with  the  occlusal  plane  paral- 
lel to  the  line  through  the  pupils  of  the  eyes. 

53 


Fig.  33 


Completing  the  Upper  Bite  Rim. 

Fill  in  any  serious  irregularities  in  the  occlusal  surface 
of  the  bite  rim  by  tracing  on  soft  compound.  Heat  the 
entire  occlusal  surface  to  a  shallow  depth  in  the  side  of  the 
bunsen  flame  and  press  upon  a  moist  glass  surface  to  make 
it  flat  and  smooth,  but  do  not  change  the  vertical  height 
or  occlusal  plane. 

Cut  notches  like  those  shown  at  "B".  These  should  be 
wide  and  flaring,  irregular  in  shape,  about  l/g  inch  deep 
and  inclined  toward  the  median  line  at  different  angles. 
These  will  insure  proper  locking  of  the  lower  bite  rim. 

54 


Fig.  34. 


Lower  Trays. 

Tt  is  advantageous  to  select  one  of  the  larger  sizes  of 
lower  impression  trays  and  shorten  it  to  fit  the  case,  be- 
cause the  larger  size  has  a  wide  flange  in  the  bicuspid  and 
molar  region,  which  will  better  support  the  compound. 

A  thin  metal,  lower  impression  tray  as  received  from 
the  maker  is  shown  at  "A".  At  "B"  is  shown  the  same 
tray  with  the  labial  flange  cut  away  from  cuspid  around 
to  cuspid  and  the  lingual  flange  partly  cut  away  in  the 
same  region  to  avoid  pressure  on  the  frenum. 

55 


Fig.  35. 


Shaping  the  Lower  Tray. 

With  contouring  pliers  spread  the  flanges  of  the  tray 
in  the  bicuspid  and  molar  region  so  that  the  lateral  con- 
tour is  flatter  than  that  of  the  ridge.  Bend  the  tray  to  fit 
the  curvature  of  the  ridge  in  the  incisor  region  and  con- 
tinue the  bending  so  that  the  tray  follows  the  curvature  of 
the  ridge  in  the  bicuspid  and  molar  region,  as  it  does  on 
the  model,  which  is  shown  here  purely  for  purposes  of 
illustration. 


56 


Fig.  3G. 

Guide  Rimming  the  Lower  Tray. 

Heat  aboul  !  ^>  inch  of  a  tracing  stick  in  the  top  of  tho 
bunsen  llanie  and  trace  compound  on  the  fitted  tray,  as 
shown.  This  compound  should  be  a  little  over  y%  inch 
in  depth  and  several  tracings  will  be  required.  If  there 
is  any  tendency  for  the  first  tracing  to  run  when  the  later 
tracings  are  made,  chill  in  cold  water.  Xote  that  the 
guide-rims  are  confined  to  the  margins  of  the  tray  and  do 
not   touch  the  center. 

To  prepare  the  guide  rims  to  go  into  the  month,  dip 
them  into  hot  water  until  they  are  of  a  consistency  which 
will  require  a  slight  pressure,  but  not  a  severe  pressure, 
to  mould.     This  will  require  from  2  to  4  seconds. 

57 


-' 


Fi?.  37. 


Inserting  the  Lower  Tray. 

Have  the  patient  open  the  month  wide  enough  to  admit 
the  tray  but  not  to  tighten  the  cheek  muscles. 

Stand  in  front  of  the  patient.  Carry  the  left  side  of  the 
tray  toward  and  into  the  month  until  the  center,  which  is 
grasped  between  the  thumb  and  finger,  touches  the  left 
corner  of  the  mouth.  Distend  the  right  corner  of  the 
mouth  with  the  index  finger  of  the  left  hand.  Rotate  the 
tray  until  the  left  side  touches  the. cheek  and  the  right  end 
passes  into  the  mouth.  Continue  the  rotation  until  the 
tray  is  approximately  centered.  Release  the  tray  and  let 
it  settle. 

58 


Fig.  38. 

Seating  the  Lower  Tray. 

Make  sure  thai  the  anterior  margin  of  the  tray  does  not 
extend  forward  beyond  the  labial  surface  of  the  Lower 
ridge.  This  will  bring  the  lower  tray  in  the  same  relation 
in  the  lower  ridge  thai  the  upper  tray  is  to  the  upper  ridge 
in  Figure  6. 

Make  lighl  pressure  over  the  parts  of  the  tray  to  which 
the  compound  is  attached.  When  this  pressure  is  properly 
made  the  tray  will  nol  be  forced  down  into  contacl  with 
the  ridge  anywhere  but  will  remain  about  1/16  inch  above 
it  all  around. 

Remove  the  tray  Immediately  from  the  mouth  and  chill 
the  compound  in  cold  water. 

59 


Fig.  39. 

Seating  the  Lower  Tray,  Continued. 

The  guide  rims  at  UA"  show  the  result  of  the  techuic  iu 
Figure  38.  The  tray  has  since  been  dried  and  soft  model- 
ling compound  traced  in  the  hollow  of  the  incisor  region. 
Place  the  tray  in  the  mouth.  Make  light  pressure  over 
the  guide  rims  as  in  Figure  38.  This  accurately  reseats 
the  tray  and  takes  an  impression  of  the  ridge  in  the  in- 
cisor region.  Do  not  apply  pressure  in  the  incisor  region 
as  it  may  tilt  the  heels  of  the  tray  upward  and  establish 
wrong  relations. 

Withdraw  the  tray ;  chill  the  compound ;  replace  the 
tray  and  test  for  stability.  If  it  is  not  stable,  repeat  the 
operation  until  it  is. 

Paint  hot  compound  from  a  tracing  stick  upon  the  lin- 
gual side  of  the  tray,  as  it  was  painted  upon  the  upper  in 
Figure  11. 

60 


Pig.  40. 


Forming  the  Lower  Bite  Rim. 

Soften  compound  and  form  a  roll  as  described  for  Figure 
24.  Bend  the  roll  to  lit  the  curve  of  the  tray  and  cut  it 
short  enough  so  that  it  does  not  extend  onto  the  upward 
incline  at  the  heels. 

Have  the  compound  in  an  easily  moulding  stage  but  not 
soft,  and  press  the  roll  against  the  tray  so  that  it  takes  the 
imprint  of  the  tray. 

This  bite  rim  should  ho  made  very  shallow  vertically  and 
should  permit  the  ridges  to  come  too  close  together  for 
crood  esthetic  results.     The  height  will  be  corrected  later. 


61 


Fig.  41. 

Attaching  the  Lower  Bite  Rim. 

Remove  the  roll  and  dry  it  and  the  tray.  Grasp  the 
bent  roll  at  the  bicuspid  region  on  the  left  side.  Bring 
the  left  heel  of  the  tray  side  of  the  roll  against  the  base 
of  the  bunsen  flame,  as  shown.  Heat  the  compound  until 
it  sputters.  Slowly  rotate  the  roll  toward  the  left,  keeping 
the  compound  and  name  in  contact  until  the  compound  has 
been  heated  to  a  sputtering  condition  the  full  length  of 
the  roll. 

Place  the  roll  in  position  on  the  dry  tray  and  press  home. 
This  makes  the  bite  rim.  Chill  the  tray  to  prevent  the 
heat  in  the  rim  softening  or  changing  the  guide  rims.  In- 
vert the  tray  and  dip  the  occlusal  surface  of  the  bite  rim 
in  hot  water  to  a  depth  of  *4  inch  until  it  can  be  easily 
moulded. 

62 


-4 


Fig.  42. 

Carrying  the  Bite  Rimmed  Lower  Tray  Into 
the  Mouth. 

Grease  the  occlusal  surface  of  the  upper  bite  rim  with 
cocoa-butter  and  place  the  upper  impression  in  the  mouth. 
( rrasp  the  hard  portion  of  the  lower  liitc  rim  as  shown  and 
carry  the  left  heel  into  the  mouth  and  sideways  against  the 
left  cheek,  at  the  same  time  distending  the  righl  corner 
of  the  mouth  with  the  left  index  finger.  Carry  the  righl 
heel  inward  past  the  finger  and  release  the  tray. 


G3 


Fig.  43. 

Placing  the  Bite  Rimmed  Lower  Tray. 

Stand  in  front  of  the  patient.  Place  both  index  fingers 
against  the  buccal  surfaces  of  the  lower  bite  rim  in  the 
bicuspid  region,  as  shown  at  "B"  and  make  pressure 
inward  and  downward.  Ask  the  patient  to  touch  the  tip 
of  the  tongue  to  the  center  of  the  vault,  as  far  back  as 
possible.  This  is  usually  near  the  heel  of  the  upper  im- 
pression. While  the  tongue  is  in  this  position,  direct  the 
patient  to  close  the  jaw  as  far  as  possible. 

Chill  the  bite  rim  with  l/o  inch  cotton  rolls  wrung  from 
ice  water,  or  with  low  pressure  air,  and  remove  it  from 
the  mouth. 


64 


B 


"> 


1 


w~ 


Pig.   44. 


Trimming  the  Lower  Bite  Rim. 

Figure  "A"  shows  the  upper  bite  rim  in  place  on  the 
lower  as  they  were  closed  together  in  the  mouth.  The 
occlusal  surface  of  the  lower  bite  rim  is  shown  at  "B". 
The  wedges  of  compound  which  filled  the  notches  in  the 
occlusal  surface  of  the  upper  rim  can  lie  seen. 

Trim  away  the  excess  compound  on  the  buccal  and  lin- 
gual surfaces  until  the  edges  of  the  impression  of  the 
upper  rim  are  reached.  Do  no1  trim  oft  the  wedges  on 
the  occlusal  surface.  Dry  the  ridge  surface  of  the  tray 
and  guide  rims.  Replace  the  upper  impression  in  the 
mouth. 


Fig.  45. 

Shaping  the  Compound  foe  the  Lower 
Impression. 

Shape  a  roll  of  compound  %  inch  in  diameter  and  as 
long  as  around  the  tray  from  heel  to  heel.  Heat  one  side 
of  the  roll  in  the  bunsen  flame  until  it  sputters  and  attach 
it  to  the  ridge  side  of  the  tray.  Mould  the  compound  so 
that  it  will  be  narrow  and  relatively  deep  at  the  median 
line,  and  wide  and  relatively  shallow  at  the  heels,  as  shown 
here.     It  should  be  concave  on  the  ridge  side. 

Heat  the  ridge  side  of  this  compound  to  a  flowing  con- 
dition with  the  mouth  blowpipe  as  shown  in  Figure  16. 
The  central  depression  of  the  compound  should  be  softened 
to  a  greater  depth  than  are  the  margins.  To  equalize  the 
temperature  and  prevent  burning  the  patient,  carry  the 
ridge  surface  into  the  hot  water  and  remove  with  a  quick, 
jerking  motion. 

66 


Pig.  4G. 


Inserting  the  Tray  for  the  Lower  Impression. 

The  lips  and  corners  of  the  patient's  month  have  been 
lightly  coated  with  white  vaseline.  Carry  the  lower  tray 
into  the  month  as  described  for  Figure  37. 

As  soon  as  it  is  in  the  month  release  it.  Place 
the  index  fingers  on  the  buccal  surfaces  of  the  bite  rim  in 
the  bicuspid  region  as  in  Figure  43  and  hold  the  bite  rim 
off  the  ridge  by  pressing  the  index  fingers  toward  each 
other  against  the  buccal  surfaces.  This  method  of  holding 
permits  the  dentist  to  move  it  or  rotate  it  as  desired. 
Request  the  patient  to  tonch  the  tongue  to  the  vault  of  the 
mouth.  Guide  the  wedges  on  the  lower  bite  rim  into  the 
notches  in  the  upper  bite  rim.  Have  the  patient  close  as 
far  as  possible  and  proceed  as  in  the  following  illustration. 

G7 


Fig.  47. 


Turning  Up  the  Surplus  Compound  on  Buccal 
and  Labial  Surfaces. 

Instruct  the  patient  to  make  a  steady  suction  or  negative 
pressure  in  the  mouth.  While  this  suction  exists,  uncler 
biting  pressure,  place  the  thumbs  on  the  side  of  the  face, 
as  shown  here,  and  press  upward  and  inward  against  the 
lower  margin  of  the  compound,  which  can  be  felt  toover- 
liang  the  border  of  the  jaw,  forcing  the  compound  against 
the  buccal  and  labial  surfaces  of  the  ridge. 

Part  the  lips  but  not  the  jaws  and  chill  the  compound 
with  cotton  rolls  wrung  out  of  ice-water,  or  with  low 
pressure  air. 

When  thoroughly  chilled,  carefully  remove  both  impres- 
sions from  the  mouth  and  immerse  in  cold  water. 

68 


Fig.   48. 

The  Incomplete  Lower  Impression. 

This  illustration  shows  the  lower  impression  as  ir  results 
from  the  manipulation  illustrated  in  the  two  figures  im- 
mediately preceding. 

Ohscrve  that  the  wedges  on  the  occlusal  surface  of  the 
lower  bite  rim  fit  into  the  grooves  in  the  occlusal  surface 
of  the  upper  hite  rim  and  maintain  correct  relations  be- 
tween the  upper  and  lower.  This  automatically  holds  the 
lower  tray  in  correct  relation  to  the  lower  ridge  as  the 
patient  bites  into  the  soft  compound  and  insures  the  taking 
of  the  impression  under  biting  stress  and  negative  pressure. 
These  are  the  most  favorable  conditions  for  taking  a  lower 
impression. 

This  method  of  forming  the  two  bite  rims  and  of  holding 
the  lower  in  a  fixed  relation  to  the  upper  while  the  lower 
ridge  is  closed  into  the  soft  compound  to  take  the  impres- 
sion is  a  complete  reversal  of  the  methods  common  for 
many  years  past.  This  method,  once  mastered,  will  he 
found  very  satisfactory. 


69 


Fig.   49. 


Trimming  the  Surplus  From  the  Lower 
Impression. 

"A"  shows  che  ridge  surface  of  a  lower  impression  as  it 
is  at  the  end  of  the  manipulation  described  in  Figures 
46  and  47. 

"B"  shows  the  same  view  of  this  impression  after  the 
manipulation  described  in  Figures  51  to  54  inclusive  was 
completed. 

Trim  away  the  surplus  which  is  shown  outside  the  white 
line  in  "A".  This  will  leave  the  flange  about  %  inch 
thick. 


The  impression  in  "B"  is  smaller  in  ridge  area  than 
that  in  "A".  This  is  due  to  the  "trimming"  described 
in  the  steps  to  follow.  A  "trimmed"  impression  is  less 
liable  to  interfere  with  the  movements  of  the  buccal  and 
lingual  groups  of  muscles  and  hence  is  more  stable  and 
comfortable. 


70 


Fig.  50. 

Technic  for  Heating  Flange  for  Muscle 
Trimming. 

In  heating  the  flanges  for  muscle  trimming,  allow  the 
heat  to  strike  only  the  compound  to  he  softened.  Invert 
the  lower  to  heat,  but  do  not  invert  the  upper.  Hold  the 
edge  of  the  flange  to  be  heated  for  muscle  trimming  against 
the  side  of  the  base  of  the  flame,  where  the  heat  is  less 
intense  than  at  the  top.  In  this  position  the  heat  is  not 
deflected  to  soften  the  compound  elsewhere. 

Heat  only  the  edge  of  the  flange  to  a  depth  of  Yg  inch 
or  as  deep  as  judgment  indicates  to  be  necessary  and  skill 
in  handling  permits. 

Heat  the  flanges  of  each  impression  in  three  sections, 
one  from  cuspid  to  cuspid,  one  from  each  cuspid  to  each 
heel.  When  one  becomes  expert,  it  may  be  possible  to 
include  two  or  more  sections  in  each  heating. 

Dip  the  heated  flange  in  hot  water.  Instantly  remove 
with  a  jerking  motion  and  quickly  place  the  impression  in 
the  mouth. 


Fig.   51. 

Trimming  Lower  Labial  Flange- 
Cuspid. 


-Cuspid  to 


Leave  out  the  upper  impression.  Heat  the  lower  labial 
flange  from  cuspid  to  cuspid.  Place  the  lower  quickly  in 
the  mouth  and  press  on  the  occlusal  surface  in  the  bi- 
cuspid region,  until  the  impression'  is  properly  and  firmly 
seated.  Have  the  patient  draw  the  lip  upward  and  in- 
ward over  the  bite  rim.  Massage  the  compound  by  thumb 
pressure  upward  and  inward  on  the  outside  of  the  lower 
lip,  beginning  a  little  below  the  heated  margin. 

Hold  the  impression  firmly  in  place  until  the  flange  has 
been  chilled  or  is  hard. 

Tf  only  a  little  surplus  is  turned  up,  it  may  not  be 
necessary  to  repeat.  A  beginner  should  repeat  until  an 
upward  pull  on  the  relaxed  lip  in  this  region  will  not 
raise  the  impression. 

72 


Fig.   52. 

Trimming  the  Lower  Buccal  Flange. 

Hear  the  buccal  flange  from  cuspid  to  heel.  Place  the 
impression  in  the  mouth  and  hold  in  place  by  pressing 
downward  with  the  first  and  second  fingers  of  the  right 
hand  in  the  bicuspid  region.  Make  heavier  pressure  on  the 
side  which  has  not  been  heated  than  on  the  heated  side. 

Stand  in  front  of  the  patient.  Grasp  the  right  check  be- 
tween the  index  and  middle  fingers  of  the  right  hand  and 
pull  it  gently  upward  and  inward  againsl  the  margin  of  the 
softened  flange.  At  the  same  time  the  thumb  may  pat  the 
heated  margin  gently  upward  and  inward,  through  the 
cheek.  This  position  cannot  be  photographed.  The  illus- 
tration shows  the  action  bul  not  the  position.  Employ  only 
gentle  pressure.    Trim  the  left  llanire  in  ;i  similar  manner. 

The  buccal  margin  may  be  regarded  as  trimmed  when 
the  pull  of  the  muscles  in  this  region  will  not  dislodge  the 
denture,  or  when  the  margin  of  the  impression  does  not 
extend  below  the  external  oblique  line. 


Fig.   53. 


Muscle  Trimming  the  Lower  Lingual  Flange 

Part  1. 

Heat  the  edge  of  the  lingual  flange  from  cuspid  to 
cuspid  in  the  manner  illustrated  in  Figure  50. 

Place  the  impression  in  the  mouth  and  make  pressure 
on  the  occlusal  surface  of  the  bite  rim  with  the  index 
fingers  of  both  hands.  Note  that  the  thumbs,  as  shown 
here  and  in  Figure  52,  are  pressed  upward  below  the 
mandible  to  assist  in  making  this  pressure. 

Cause  the  patient  to  place  the  tongue  either  between  the 
upper  ridge  and  the  upper  lip  or  outside  the  upper  lip,  at 
the  same  time  moving  it  from  side  to  side. 

74 


Fig.   54. 


Muscle  Trimming  the  Lower  Lingual  Flange 

Part  2. 

Heat  the  edii'c  of  the  left  flange  from  cuspid  to  heel, 
in  I  he  manner  descrihed.  Place  the  lower  impression  in 
the  mouth,  the  upper  being  out,  and  hold  in  place  as  de- 
scribed for  Figure  53. 

Cause  the  patienl  to  open  the  mouth  ;is  wide  as  pos- 
sible and  to  then  try  to  lick  with  the  tongue  between  the 
right  cheek  and  the  righl  upper  and  lower  alveolar  ridges, 
in  the  region  of  the  second  molar. 


Fit 


Trimming  the  Buccal  Flange. 

The  white  line  in  "A"  shows  a  foreshortened  view  of 
the  white  line  in  "B"  and  the  area  marked  "C"  is  the 
same  in  both  figures.  The  margin  of  the  compound  to  the 
left  of  the  white  line  in  "A"  shows  first  a  depression  and 
then  a  mound.  This  mound  is  composed  of  the  compound 
which  has  been  forced  downward  so  that  it  bears  too  heavily 
upon  the  muscles  and  if  reproduced  in  the  denture  would 
cause  irritation,  when  the  muscles  on  which  it  rests  come 
into  play.  The  compound  outside  the  white  line  in  "B" 
should  be  trimmed  to  the  contour  of  the  dotted  line  "C" 
in  UA".  The  section  of  the  flange  here  shown  at  "C" 
corresponds  to  the  section  of  the  flange  represented  as 
extending  below  the  external  oblique  line  in  the  next 
illustration. 

All  denture  margins  should  be  rounded  and  pulley  like, 
rather  than  sharp.  This  form  permits  the  muscles  to  play 
over  them  without  irritation. 


SPINE  AT 

MYLOHYOID 

LINE 

COMPOUND 
FLANGE 


Fig.  50. 

The  Relation  of  the  Lower  to  the  Ridge 

The  diagram  above  shows  a  section  through  a  flat  lower 
jaw,  the  impression,  the  tray  and  the  bite  rim  in  the  region 
of  the  second  molar.  The  flanges  here  shown  extend 
below  the  external  oblique  line  and  the  mylo-hyoid  line, 
as  they  arc  sometimes  Left  after  mnscle  trimming.  It'  the 
plate  is  made  with  the  flanges  in  this  position,  the  muscles 
which  were  easily  depressed  in  muscle  trimming  may  prove 
active  enough  to  develop  considerable  irritation  at  the 
point  where  the  tissues  chafe  against  the  flange. 

The  buccal  and  lingual  flanges  should  not  extend  below 
the  level  of  muscle  attachment  at  the  external  oblique  and 
mylo-hyoid  lines  respectively  unless  a  slight  extension  is 
necessary  to  develop  "suction." 

Tf  the  ridge  is  flat,  it  may  be  necessary  to  trim  the 
flanges  to  the  form  of  dotted  outline.  The  impression 
should  he  trimmed  so  thai  when  the  finger  is  passed 
downward  across  its  lingual  surfaces  the  flanges  will 
appear  to  he  continuous  with  the  hard  tissues  ol  the  man 
dible  at  the  level  of  the  mylo-hyoid  line. 

When  the  teeth  occupy  the  relation  to  the  rfdge  shown 
by  the  dotted  tooth  outline,  the  muscular  action  of  the 
cheek  and  tongue  will  balance  each  other  and  the  denture 
will  have  maximum  stability. 

77 


Fig.   57. 

Stabilizing  the  Lower  Impression. 

The  lower  impression  should  now  exhibit  "suction''  and 
be  stable  on  the  ridge  against  direct  vertical  pressure  on 
the  occlusal  surface  at  any  point  between  the  first  molar 
locations:  or  against  a  rocking  pressure  applied  in  the 
bicuspid  region.  If  it  is  not  stable,  some  error  has 
occurred  in  manipulation. 

Place  the  upper  impression  in  the  mouth.  To  correct 
the  error  in  the  lower,  hold  the  impression  as  shown  and 
direct  a  sharp-pointed,  mouth  blow-pipe  alcohol  flame 
against  the  compound  which  lies  in  contact  with  the  crest 
of  the  ridge.  Avoid  overheating  the  compound  or  deflect- 
ing the  heat  against  the  flanges.  Apply  the  flame  first  at 
the  top  of  the  left  heel,  and  move  it  evenly  along  the  bottom 
of  the  valley  of  the  impression,  so  as  to  reach  the  other 
heel  in  about  one  second.  Have  the  flame  make  a  return 
trip  from  heel  to  heel.  Repeat  this  three  times.  Dip  the 
lower,  thus  heated,  into  hot  water.  Instantly  remove  it 
with  a  jerking  motion  and  place  in  the  mouth.  .  Cause  the 
patient  to  place  the  tip  of  the  tongue  in  the  rear  of  the 
center  of  the  vault  and  close  the  mouth,  swallow  and  suck, 
while  holding  the  bite  rims  in  contact.  Allow  the  impres- 
sion to  harden  thoroughly,  remove ;  chill  in  cold  water  and 
test  for  stability. 

78 


Pig. 


Heating  the  Upper  Buccal  Flaxge  for  Muscle 
Trimming. 

The  upper  impression  is  to  be  muscle  trimmed  under 
biting  pressure  with  the  mouth  closed.  This  is  opposite 
to  the  practice  for  the  Lower,  which  was  trimmed  with  the 
mouth  open. 

Hold  the  right  buccal  flange  of  the  upper  in  contact  with 
the  side  of  the  bunsen  flame,  near  its  base,  as  shown,  with 
the  impression  tilted  to  the  inclination  shown. 

Soften  the  edge  of  the  flange  from  cuspid  to  tuberosity 
to  a  vortical  depth  of  Yg  inch. 

The  first  heating  should  be  from  heel  to  cuspid. 

Dip  in  hot  water,  remove  as  quickly  as  possible  and 
carry  to  the  mouth. 

79 


59. 


Muscle  Trimming  the  Upper  Buccal  Flanges 

The  trimmed  lower  impression  is  in  the  month.  Stand 
in  front  of  the  patient  and  place  the  upper  impression  in 
the  mouth,  left  side  first.  Protect  the  softened  right  flange 
while  entering,  by  distending  the  right  corner  of  the 
mouth  with  the  left  index  finger.  Seat  the  impression  by 
upward  ancl  backward  pressure  with  the  right  index  finger 
in  the  center  of  the  vault.  Cause  the  patient  to  close, 
swallow  and  suck  with  the  bite  rims  in  contact. 

Soften  the  edge  of  the  left  buccal  flange.  Stand  be- 
hind the  patient,  distend  the  left  corner  of  the  mouth 
with  the  left  index  finger,  enter  the  impression  right  heel 
first,  rotate  to  position  and  have  the  patient  close  and 
swallow. 

80 


Fig.   60. 

Muscle  Trimming  the  Labial  Flange  oe  the 
[Jppek  Impression,  Part  l. 

Heal  the  margin  of  the  flange  Prom  the  firsl  bicuspid  on 
one  side  to  the  firsl  bicuspid  on  the  other,  using  the  technic 
described  for  Figure  58.  Equalize  the  temperature  in  hoi 
water,  place  in  the  mouth  in  the  same  manner  as  before. 
Cause  the  patienl  to  close  upon  the  bite  vims  and  to 
throw  the  lips  forward  as  here  shown  and  backward  as  in 
Figure  61. 


SI 


^•OB1 


Fig.   61. 

Muscle  Tkimming  the  Labial  Flange  or  the 
Upper  Impression,  Part  2. 

Before  causing  the  patient  to  make  the  forward  and 
backward  lip  movements,  the  dentist  should  demonstrate 
these  movements  by  performing  them  himself  and  then 
give  the  patient  a  mirror  and  cause  her  to  practice. 

It  is  sometimes  advisable  to  stand  behind  the  patient  and 
place  the  index  fingers  on  the  upper  lip  and  when  the  for- 
ward movement  is  to  be  made,  push  the  lip  forward,  and 
when  the  backward  movement  is  to  be  made,  pull  it  back. 
These  movements  should  be  deliberate  and  rhythmical. 

The  result  of  muscle  trimming  is  to  provide  a  Avorking 
space  for  the  muscles  in  contact  with  the  upper  denture, 
so  that  ordinary  movements  will  not  destroy  its  stability. 

82 


Fig.   G2. 


Outlining  Areas  for  Compression  and  Relief. 

Locate  first  the  posterior  palatine  foramina,  marked 
"A  A"  in  this  illustration.  Those  can  best  he  located  by 
pressing  a  ball  ended  instrument  against  the  tissues  over- 
lying the  palatine  artery  commencing  at  the  first  molar, 
and  moving  it  backward,  with  pressure  upward  and  out- 
ward, until  it  tits  into  the  depression  over  the  foramen. 
Roll  cotton  tightly  on  pliers  or  a  match,  moisten  ir  with 
water  and  wipe  the  mucin  from  the  tissues  in  this  region. 
With  a  soft  indelible  pencil,  mark  a  circle  about  3/16  inch 
in  diameter,  enclosing  the  area  over  the  foramen.  It  is 
no1  uncommon  for  the  hard  palate  to  present  a  spine  jusl 
posterior  to  the  foramen.  Such  a  spine  can  lie  detected 
with  the  ball  end  instrument  and  the  area  it  occupies 
should  bo  included  within  the  circle.  Make  the  same 
examination  and  mark  over  the  opposite  foramen. 

To  provide  relief  over  the  anterior  palatine  foramen, 
also  marked  "A",  draw  a  circle  about  the  base  of  the  most 
anterior  papilla  of  the  rugae. 

83 


The  dotted  lines  "B-B"  show  how  far  forward  the  soft 
tissue  may  extend  in  some  cases.  No  compression  of 
these  tissues  should  be  made  anterior  to  the  palatine  fora- 
mina nor  over  them,  for  fear  of  shutting  off  the  circulation 
in  the  vessels  which  emerge  here. 

The  area  of  soft  tissues  which  may  properly  be  com- 
pressed to  perfect  the  fit  of  the  posterior  part  of  the  denture 
to  the  vault,  is  bounded  by  the  solid  black  line  "C".  Draw 
the  crescent  shaped  lines  "C"  by  starting  at  the  bottom 
of  the  notch  behind  either  tuberosity  and  moving  the 
pencil  inward  and  forward  to  the  posterior  margin  of  the 
circle  around  the  palatine  foramen  and  the  spine,  if  pres- 
ent, and  then  to  the  anterior  margin  of  the  compressible 
soft  tissue  at  the  median  line. 

The  hard  unyielding  tissues  in  the  center  of  the  mouth 
are  usually  located  within  the  area  marked  "D".  Deter- 
mine the  form  and  extent  of  this  area  in  each  case  with 
the  ball  end  instrument  and  mark  the  boundaries  on  the 
tissues. 

Relief  Over  the  Course  of  the  Palatine 
Artery. 

It  sometimes  happens  that  an  upper  impression  prop- 
erly taken  and  trimmed  will  have  stability  and  fit  tightly 
but  after  a  minute  or  more  will  be  forced  out  of  place 
without  muscular  movement  by  the  patient.  In  such  cases 
examine  the  impression  for" air  leaks  at  the  margins.  Make 
sure  that  muscle  trimming  is  complete.  When  satisfied 
that  there  are  no  air  leaks  and  no  muscle  strain,  relieve  the 
impression  over  the  palatine  foramina  and  along  the  course 
of  the  palatine  artery.  This  usually  results  in  the  reten- 
tion of  the  impression. 

In  some  mouths  the  rami  pass  so  close  to  the  tuberosity, 
in  the  opening  movement,  that  one  of  them  may  thrust 
the  impression  downward  and  forward.  In  such  cases 
trim  the  impression  material  over  the  tuberosity  very  thin. 

84 


Fig.  63. 

Transferring  Markings  to  Impression. 

Press  the  dried  impression  against  the  roof  of  the  month 
for  a  second  or  two,  hold  with  a  slight  rotary  motion. 
Remove.  This  should  transfer  to  the  impression  the  bine 
lines  made  in  the  mouth.  Engrave  these  lines  into  the 
Impression  with  a  pointed  instrument.  It  is  not  desirable 
to  CU1  the  relief  ;it  this  time  if  records  are  to  be  taken  for 
the  Adaptable  Articulator,  because  the  creating  of  the 
proper  relief  mighl  allow  the  impression  to  move  slightly 
during  lateral  movements  of  (lie  mandible. 

Those  who  are  nol  to  employ  that  articulator  and  de- 
sire In  make  the  relief  QOW,  ;ire  referred  to   Figure  oO. 


85 


Fig.  G4. 


Impression  Marked  for  Relief. 

The  area  "A"  is  the  location  of  the  relief  over  the  hard 
tissues  of  the  median  suture.  "B"  "B"  aB"  are  located 
over  the  palatine  foramina.  The  area  "C"  is  that  of 
the  compressible  soft  tissues,  over  which  material  may  be 
added  to  the  impression  with  the  idea  of  compressing  these 
tissues  more  than  they  otherwise  would  be.  The  right 
side  of  this  area  is  here  shown  with  wax  added.  This  is 
the  black  wax  on  which  Trubyte  teeth  are  carded.  Boll  a 
small  portion  between  the  fingers  until  it  is  soft  and 
mould  over  the  area  to  present  a  thin  edge  in  front  and  a 
rounded  edge  at  the  rear.  Have  the  wax  thin  at  the 
median  line  and  the  tuberosities  and  gradually  thicken  to 
about  %  millimeter,  half  way  between  the  two. 

The  lower  impression  is  in  the  mouth.  Place  the  upper 
immediately  in  the  mouth  and  cause  the  patient  to  close 
and  swallow  several  times.  This  moulds  the  wax  to  a  pres- 
sure fit  with  the  soft  tissues, 


86 


Fig.   G5. 

Trimming  the  Upper  Impression  at  the 
Frenum. 

Note  whether  a  slight  downward  pull  on  the  upper  lip 
causes  the  frenum  to  pull  too  strongly  against  the  flange  of 
the  impression.  If  it  does,  heat  the  bottom  of  the  frenum 
notch  to  a  depth  of  ahout  ys  inch,  using  a  mouth  blow- 
pipe and  nn  alcohol  flame.  Dip  in  hot  water,  quickly 
place  in  I  lie  mouth  and  hold  as  shown  and  have  the  pa- 
tient move  the  lip  downward  as  illustrated. 

When  the  ridge  is  very  hard  and  the  frenum  active  and 
attached  near  the  crest  of  the  ridge,  only  a  slight  downward 
lip  movement  is  permitted,  since  "suction"  may  be  lost 
if  heating  or  lip  action  is  carried  too  far. 

Thorough! v  chil!  the  impression  and  test  for  "suction" 
by  causing  the  patient  to  perform  the  lip  movements  in 
Figures  60  and  61  while  pronouncing  such  words  as 
"W-h-a-t". 


87 


Fig.   GG. 

Perfecting  Adaptation  of  the  Upper  Flange 
to  the  Ridge. 

If,  following  the  foregoing  manipulation,  the  upper  im- 
pression is  stable  on  the  ridge,  but  is  easily  dislodged  by  lip 
or  cheek  movements,  as  in  pronouncing  the  word  "when," 
and  it  is  known  that  the  posterior  margin  has  been  post- 
dammed  so  that  no  leak  exists  there,  the  fault  will  be  found 
in  imperfect  adaptation  of  the  buccal  and  labial  flanges  to 
the  ridges.     It  may  be  corrected  as  follows : 

Place  the  lower  impression  in  the  mouth.  Dip  the  buc- 
cal flange  of  one  side,  from  cuspid  to  heel,  in  water  of  a 
temperature  of  115°  or  120°  F.,  for  about  10  seconds,  or 


until  it  is  softened  to  the  bending  stage.  Place  the  upper 
impression  carefully  in  the  mouth,  entering  the  softened 
flange  last,  and  have  the  patienl  close.  By  very  lighl 
finger  pressure  directly  on  the  flange,  bend  il  to  adaptation 
to  the  ridge  and  theu  have  the  patienl  suck.  Adapt  the 
oilier  buccal  flange  in  the  same  way. 

The  labial  section  of  the  flange,  after  softening,  may  be 
adapted  by  drawing  the  lip  tightly  down  upon  ii  with  the 
thumbs,  or  by  drawing  a  towel  tightly  across  it  while  the 
pal  ient  sucks. 

Tf  muscle  trimming  has  been  properly  performed,  the 
impression  should  now  be  well  retained  against  all  lip  and 
cheek  movements. 


The  Heights  of  the  Bite  Rims. 

It  is  important  to  the  stability  of  the  lower  denture  and 
to  the  patient's  comfort  to  trim  the  lower  bite  rim  to  the 
proper  fullness  and  height. 

First  trim  the  labial  flange  of  the  impression  thin 
enough  to  prevent  the  lip  exerting  any  backward  pressure 
and  forcing  the  impression  off  the  ridge,  a  condition 
which  causes  the  failure  of  many  lowers.  The  flange 
should  not  he  thinner  than  1/16  inch,  except  in  some 
recent  extraction  or  undercut  cases,  where  it  is  entirely  cut 
away. 

Trim  the  labial  surface  of  the  bile  rim  to  the  exact  po- 
sition desired  for  the  labial  surfaces  of  the  lower  an- 
teriors.  This  should  be  such  that  the  incisors  will  rest 
upon  the  ridge,  rather  than  in  front  of  it,  and  the  centers 
of  gravity  of  the  teeth  will  he  directly  over  the  crest  of  the 
ridge. 

Bring  the  occlusal  surface  of  the  lower  bite  rim.  from 
cuspid  to  cuspid,  six  to  eight  millimeters  above  the  crest 
of  the  lower  ridge,  by  trimming  or  adding  compound.  If 
the  sections  from  cuspids  to  heels  are  too  high,  soften  the 

89 


occlusal  surface  in  the  bunsen  flame,  dip  in  hot  water,  place 
in  the  mouth,  the  upper  being  in  place,  and  have  the  pa- 
tient close  until  the  rims  come  together  in  front.  If  the 
sections  from  cuspids  to  heels  are  too  low,  add  soft  com- 
pound until  they  are  a  little  too  high  and  have  the  patient 
close  the  bite  rims  together  in  front. 

To  enable  the  patient  to  drink  comfortably,  the  lower 
incisors  must  not  extend  above  the  relaxed  lower  lip.  The 
lip  and  tongue  can  then  easily  rise  above  them  and  form 
a  joint  with  the  glass  or  cup  and  prevent  fluid  from  getting 
between  the  lip  and  teeth.  If  the  teeth  are  too  high  to 
permit  forming  this  joint,  fluid  will  go  down  inside  the 
lip  and  under  the  plate. 

Trim  the  upper  bite  rim  to,  such  a  height  that  when  the 
mouth  is  at  rest  there  will  be  an  open  space  of  about  3/16 
inch  between  the  upper  and  lower  rims  in  front. 

When  the  jaw  is  at  rest  the  lower  teeth  are  out  of  con- 
tact with  the  uppers  sufficiently  to  allow  the  tongue  to 
spread  between  the  sets  and  partly  over  the  occlusal  sur- 
faces of  the  lower  bicuspids  and  molars.  The  face  ex- 
hibits its  normal  expression  when  it  is  at  rest  with  the 
lips  closed  and  the  teeth  thus  out  of  contact.  If  the  height 
of  the  bite  rims  provides  for  this  habit,  the  dentures  will 
be  more  comfortable  and  stable,  the  teeth  will  not  click  in 
speech  and  they  will  be  more  efficient  in  mastication  than 
if  the  rims  are  so  high  as  to  prevent  the  teeth  dropping  out 
of  contact. 

To  determine  the  height  of  the  upper  bite  rim,  stand  in 
front  of  the  patient  and  cause  her  to  pronounce  such 
words  as  "Mississippi"  or  "When".  Watch  the  lower  bite 
rim.  If  it  approaches  the  upper  to  within  less  than  3/16 
inch,  trim  the  upper  until  this  amount  of  separation  is 
established.  To  do  this,  mark  the  upper  rim  as  in  Figure 
30  and  with  a  sharp  knife  trim  to  the  line.  Slightly  soften 
the  trimmed  surface  in  the  flame,  dip  in  hot  water,  place 
in  the  mouth  and  have  the  patient  close  it  against  the 
lower  rim..    This  will  remove  slight  irregularities. 

90 


l^^fl 


4-\ 


Fig.   G7. 

If  the  separation  exceeds  3/16  inch,  add  compound  and 
have  t lie  patient  close  with  biting  pressure.  Repeat  until 
the  desired  separation  is  secured. 

In  cases  where  the  teeth  have  been  recently  extracted, 
and  rather  rapid  settling  is  expected,  it  is  advisable  to  re- 
duce the  amount  of  separation  between  the  bite  rims  in 
pronouncing  these  words,  to  y$  inch  or  less.  This  will 
cause  some  discomfort  at  first  but  the  settling  -will  soon 
produce  the  required  space. 

In  Figure  CT  both  bite  rims  have  boon  trimmed  :i>  di- 
rected above  and  the  tongue  shows  in  the  space  between 
them. 

91 


Fig.    08. 

Restoring  Facial  Expression,  Part  1. 

The  changes  in  the  expression  of  the  face  about  the 
mouth  following  the  loss  of  the  teeth  are  well  shown  in  this 
illustration.  The  upper  lip  has  fallen  backward  so  that 
its  margin  is  actually  behind  the  margin  of  the  lower, 
which  has  also  fallen.  The  corners  of  the  mouth  have  sunk 
inward  and  drooped  vertically. 

These  conditions  offer  dentists  opportunities  for  the 
exercise  of  a  high  degree  of  artistic  skill  in  making  den- 
tures which  support  the  jaw  in  correct  vertical  position 
and  carry  the  soft  tissues  back  to  approximately  the  posi- 
tions they  formerly  occupied. 

These  conditions  also  offer  unexcelled  opportunities  to 
interest  patients  in  the  operations  involved  in  professional 
denture  service. 


92 


PWe 


^2 


Fis;.   G9. 


Restoring  Facial  Expression,  Part  2. 

If,  when  the  impressions  are  in  place,  the  expression  of 
the  lips  seen  full  front  and  iu  profile  is  not  pleasing, 
modify  the  Labial  surface  of  the  upper  bite  rim.  If  the 
upper  lip  is  not  sufficiently  prominent,  add  to  the  labial 
surface,  from  cuspid  to  cuspid,  a  layer  of  softened  com- 
pound slightly  in  excess  of  the  amount  likely  to  be  re- 
quired. Mould  il  to  be  thicker  iu  the  median  line  than 
elsewhere,  and  place  in  the  mouth  while  it  is  soft.  By 
pressure  on  the  outside  of  the  lip.  mould  il  until  the  lip 
assumes  the  desired  contour. 

The  excess  compound  will  be  forced  downward  and 
should  be  trimmed  off  level  with  the  piano  of  occlusion. 

93 


Fig.  70. 


Restoring  Facial  Expression,  Part  3. 

In  the  ideal  Caucasian  profile  the  upper  lip  overhangs 
the  lower  about  as  shown  in  this  figure.  When  trimming 
for  expression  is  finished,  the  incisal  edge  of  the  upper 
bite  rim  should  project  about  2y2  millimeters  (a  little 
less  than  %  inch)  in  advance  of  the  incisal  edge  of  the 
lower  bite  rim.  If  this  projection  of  the  upper  bite  rim 
is  not  sufficient  to  establish  the  profile  about  as  here 
shown,  add  more  compound. 

This  projection  of  the  upper  bite  rim  also  turns  the 
edge  of  the  lower  lip  outward  and  assists  in  giving  it  a 
pleasing  expression. 

94 


Fie.  71. 


Compound-Plaster  Impressions. 

For  dentists  who  feel  that  the  use  of  plaster  in  finish- 
ing upper  impressions  is  a  short  cut  in  time  and  for  those 
who  find  difficulty  in  mastering  the  technic  for  full  com- 
pound impressions,  the  following  directions  will  be  help- 
ful. In  many  mouths  in  Class  2  and  practically  all  mouths 
in  Classes  3  and  4,  the  results  obtained  with  proper  com- 
pound technic  are  probably  impossible  with  plaster,  even 
when  it  is  supported  by  compound,  unless  the  soft  tissues 
of  the  ridge  have  been  surgically  removed. 

To  use  plaster  for  the  complete  upper  impression  to  the 
best  advantage  the  technic  for  compound  impressions 
should  be  followed  until  muscle  trimming  has  been  com- 
pleted, as  described  for  Figure  GO.  After  that,  place  the 
lower  impression  in  the  mouth.  Coat  the  upper  impres- 
sion with  a  thin  layer  of  quick  setting  impression  plaster 
mixed  to  a  creamy  consistency.  Place  the  impression  in 
the  mouth  and  cause  the  patient  to  hold  it  in  position  by 
biting  pressure.  When  the  plaster  is  hard,  remove  the 
impression  and  trim  away  the  compound  wherever  it  shows 
through  the  plaster.  Remove  all  the  plaster  from  the  im- 
pression and  with  a  tracing  wheel  roughen  the  palatal 
surface  of  the  impression  as  shown  above.  Coat  the  rough- 
ened surface  with  a  uniform  layer  of  quick  setting  model 
plaster  of  a  creamy  consistency,  and  again  place  the  im- 
pression in  the  mouth;  the  lower  being  out  of  the  mouth. 


9o 


With  a  rocking  motion  press  the  upper  firmly  against 
the  upper  ridge  and  hold  it  there  exerting  pressure  upward 
and  backward  npon  the  centre  of  the  palate  portion  of  the 
impression.  When  a  test  mass  of  plaster  is  hard,  remove 
the  impression  from  the  month  and  immerse  in  cold  water 
until  it  is  set.  Soften  the  occlusal  surface  of  the  upper 
bite  rim  and  equalize  the  biting  pressure  by  having  the 
patient  close  the  lower  against  the  upper. 

The  outline  of  the  areas  to  be  relieved  may  be  marked 
on  the  palate  and  transferred  to  the  impression  as  they 
were  on  the  compound  impression.  The  lines  may  then 
be  graven  slightly  in  the  plaster  and  relief  established  by 
adding  thin  air  chamber  metal  to  the  cast  before  form- 
ing the  base  plate. 

Wax  may  be  added  to  the  back  of  the  impression  to 
compress  soft  tissue  if  desired. 

This  method  may  be  extended  to  the  lower  impression, 
but  we  believe  it  more  difficult  to  employ  it  successfully 
than  to  employ  the  method  described  for  compound  lowers. 

Plaster  Upper  Compound  Lower. 

Dentists  who  desire  to  employ  full  plaster  impressions 
for  upper  combined  with  compound  lowers  may  do  so  by 
taking  an  upper  plaster  impression  and  shaping  a  base- 
plate over  the  cast  made  from  it  and  attaching  a  bite  rim 
to  the  baseplate.  Notches  should  be  cut  in  the  occlusal 
surface  of  this  bite  rim  in  the  manner  described  for 
Figure  33.  The  technic  for  the  lower  may  then  be  fol- 
lowed. After  the  lower  impression  is  complete,  the  upper 
baseplate  may  be  examined  and  its  margins  trimmed  with 
a  knife  until  the  action  of  the  muscles  cannot  displace  it. 
Quick  setting  model  plaster  may  then  be  flowed  into  the 
baseplate  and  a  new  upper  impression  taken,  which  will 
probably  be  more  accurate  than  the  first  impression. 

96 


Part  II 

Selecting  The 
Size,  Form  and  Shade 

In 

Artificial  Teeth 


Fig.   72. 


Marking  the  Median  Line. 

It  is  important  to  esthetic  effects  to  correctly  locate  the 
median  line  on  both  bite  rims.  This  can  be  done  by  using 
as  guides  a  point  half-way  between  the  eyes  on  the  bridge 
of  the  nose  and  one  in  the  center  of  the  chin,  dis- 
regarding the  deflection  to  which  the  tip  of  the  nose  is 
subject. 

Extend  the  median  line  the  full  width  of  the  upper  and 
lower  bite  rim  and  cut  a  notch  at  its  upper  end  to  preserve 
its  location  during  the  use  of  the  Incisor  Path  Marker. 

98 


Fi.L 


Locating  the  Distal  Sides  of  the  Cuspids. 

There  is  no  fixed  rale  for  determining  the  positions  of 
the  cuspids  which  will  be  mosl  pleasing.  The  following 
plan  is  satisfactory. 

Stand  at  one  side  of  the  patient.  With  the  bite  rims 
closed  together,  have  the  patienl  raise  the  lip  as  high  as 
possible  in  the  median  Line  and  over  the  cuspids.  Assisl  in 
the  raising  by  lightly  tapping  the  edge  of  the  Lip  upward. 

Marl?  the  upper  bite  rim  3/16  inch  in  front  of  the  corner 
of  the  orifice  on  each  side,  when  the  lip  is  raised  as  di- 
rected.    These  marks  will  satisfactorilv  locate  the  distal 


99 


Fig.    74. 


angles  of  the  upper  cuspids  in  any  mouths  save  the  very 
large  and  the  very  small.  If  the  mouth  is  large  and  the 
lips  thin  and  active,  locate  the  marks  5/16  inch  in  front 
of  the  corners  of  the  orifice.  If  the  mouth  is  small  and  the 
lips  inactive,  locate  the  marks  directly  at  the  corners  of 
the  orifice. 

Have  the  patient  smile.  Decide  whether  anteriors  as 
wide  as  between  the  marks  will  appear  well.  If  necessary, 
move  the  marks.  The  average  person  exposes  all  of  the 
first  bicuspids  in  smiling  and  laughing. 

Make  a  vertical  mark  across  both  bite  rims  Vo  inch  back 
of  the  cuspid  on  each  side. 

100 


■ 


Fig. 


Measuring  fob  Width  of  Uppek  Anteriors. 

Remove  the  upper  impression  from  the  month  and  place 
the  edge  of  a  Twentieth  Century  .Millimeter  Measure  par- 
allel to  the  incisa]  edge  and  about  Yg  iuch  above  it,  as  shown 
here.  Place  the  20  mm  mark  on  the  location  for  the  righl 
cuspid,  hold  the  celluloid  in  contact  with  the  bite  from 
cuspid  to  cuspid  and  nolo  the  reading  at  the  left  cuspid 
location,  and  subtract  20  from  it.  This  will  give  the  com 
bined  width  of  the  upper  six  anteriors  which  will  set  up  to 
the  fullness  of  the  bite  and  bring  the  cuspids  in  correct 
positions.  This  information  is  of  special  value  to  the 
careful  worker,  since,  when  used  in  connection  with  the 
tables  of  dimensions  on  page  114.  it  facilitates  rapid  and 
sal  isfactory  select  ion. 

When  upper  and  lower  dentures  are  being  made  to 
gether,  there  is  no  need  to  take  measurements  of  the 
lowers. 

101 


Fig.   TG. 


Fig.   77. 


IIARMONY  OF  FORM  ILLUSTRATED 
The  face  in  repose  is  of  square  form  an 
medium  proportions.    The  upper  centrals  arc 
of  similar  form  and  proportions. 

Figure  78  shows  the  shadow  of  the  natural 
upper  central,  enlarged  to  the  width  of  the 
face  between  the  condyles  and  imposed  on  the 
face.  It  follows  the  facial  outline  perfectly. 
Figure  79  shows  the  shadow  of  the  Trubyte 
upper  central  indicated  for  the  case  mould 
2E,  which  is  fully  as  harmonious  with  the 
face  as  tiie  natural  central. 


Fig.   78. 


102 


Harmony  of  Form  in  Faces  and  Teeth. 

I>r.  Williams  has  demonstrated  a  striking  relation  be- 
tween the  outline  forms  of-  faces  and  outline  forms  of 
upper  central  incisors  in  enough  cases  and  under  enough 
conditions  to  permil  the  formulation  of  the  following 
law:  I"  it'*1  lines!  natural  dentures,  the  outline  form  of 
the  upper  central  is  identical  with  the  outline  of  certain 
port  ions  of  the  face. 

This  law  is.  capable  of  exhaustive  proof.  Select  a 
natural  denture  which  is  pleasing  when  critically  studied 
in  relation  to  the  face  as  in  Figure  77.  Photograph  the 
upper  central  and  enlarge  it  to  he  as  wide  as  the  face  at 
the  condyles.  Impose  the  photograph  of  the  tooth  on  a 
photograph  of  the  face,  with  the  neck  of  the  tooth  at  the 
chin  margin  as  in  Figure  78.  The  photograph  of  the  tooth 
will  uniformly  extend  to  the  brow  line,  two-thirds  way 
from  the  root  of  the  nose  to  the  normal  hair  line.  The 
inverted  tooth  outline  will  follow  the  face  outline  in  a 
striking  manner. 

Nature  evidently  desires  that  the  outline  form  of  the 
face  and  of  the  upper  centrals  shall  he  identical.  She 
achieves  this  result  in  a  comparatively  small  percentage  of 
people;  these  furnish  our  finest  examples  and  maintain 
our  inspiration  and  furnish  the  basis  for  our  laws.  In  the 
great  majority  of  people  the  outlines  of  the  face  and  teeth 
are  approximately  alike  and  the  teeth  are  pleasing  when 
not  too  critically  studied.  Tn  some  people  the  face  outline 
and  tooth  outline  are  visibly  unlike  and  the  teeth  are  not 
pleasing.* 

There  is  no  relation  between  the  color  of  the  complexion 
and  the  outline  form  of  the  teeth,  as  was  claimed  by  the 
temperamental  theory. 


Those  desiring  further  illustrations  of  this  form  of  proof  are 
referred  to  the  book,  "Trubyte  Teeth  for  Vulcanite  Plates,"  pub- 
lished by  The  Dentists'  Supply  Co.,  and  sent  free  on  request. 

L03 


When  selecting  for  edentulous  cases,  pay  no  attention 
to  the  form  of  the  lost  natural  teeth,  but  select  an  arti- 
ficial form  which  harmonizes  with  the  facial  outline.  This 
will  insure  the  selection  of  long  teeth  for  long  faces,  short 
teeth  for  short  faces,  narrow  teeth  for  narrow  faces,  and 
wide  teeth  for  wide  faces,  together  with  the  proper 
straightness  or  convexity  of  outline  form.  If  the  natural 
teeth  were  harmonious  with  the  face,  this  method  will  re- 
produce them;  if  they  were  inharmonious,  artificial  teeth 
selected  in  this  way  will  improve  upon  them. 

Figure  79  shows  a  photograph  of  the  Trubyte  upper 
central  indicated  for  this  face,  enlarged  and  inverted  as 
the  natural  central  is  in  Figure  78.  When  subjected  to 
this,  the  most  exhaustive  test  so  far  devised,  the  artificial 
form  is  seen  to  be  quite  as  harmonious  with  the  face  as 
the  natural  form  in  Figure  78. 

Trubyte  teeth  are  offered  in  graded  sizes  and  selection 
of  the  desired  size  can  be  best  effected  by  the  marks  of  the 
lip  positions  on  the  compound  as  already  described. 

The  selection  for  both  form  and  size  can  be  most 
quickly  and  satisfactorily  completed  by  the  use  of  a  Mould 
Guide.  While  a  Mould  Guide  can  be  used  by  one  who 
knows  nothing  about  face  forms,  it  can  be  more  quickly 
and  satisfactorily  used  if  one  will  master  at  least  the 
elements  of  face  and  tooth  form  as  summarized  in  the 
following  pages. 


Anterior  Tooth  Forms  In  Partial  Cases. 

When  selecting  teeth  for  a  partial  case  in  which  natural 
centrals  remain,  select  a  form  of  artificial  teeth  which 
duplicates  the  remaining  central,  without  regard  to  the 
face  form.  If  only  the  natural  laterals  remain,  the  central 
may  be  selected  to  harmonize  with  the  face  form. 

104 


Brow  line 


Fig.    SO. 


Harmony  of  Form  in  Faces  and  Teeth, 
Continued. 


The  continuous  Mack  outline  encloses  the  areas  of  the 
face  with  which  the  ideal  central  will  harmonize. 

Starting  with  the  neck  of  the  inverted  upper  central  at 
the  margin  of  the  chin,  the  cervical  third  of  the  tooth  out- 
line will  follow  the  outline  of  the  lower  margin  of  tin1 
jaw;  the  outline  of  the  middle  third  of  the  tooth  will  fol- 
low the  outline  of  the  cheeks;  and  the  incisal  edge  will  he 
at  the  brow  line,  about  two-thirds  distance  from  the  root 
of  the  nose  to  the  normal  hair  line. 

Selection  for  lull  cases  may  he  confined  to  the  form  and 
size  of  the  centrals,  because  in  properly  formed  teeth,  they 
host  express  the  character  of  the  set  and  are  well  sup- 
ported by  the  same  character  in  the  laterals  and  cuspids. 

105 


Wide  forehead 
Sides  of  head 


Fig.   81. 


Typal  Square  Faces. 

There  are  only  three  typal  forms  in  faces  and  teeth, 
the  typal  square,  illustrated  and  described  above,  the  typal 
tapering  and  the  typal  ovoid.  All  other  forms  have  been 
made  by  Mendings  of  these  three.  There  are  thousands  of 
such  Mendings,  each  with  its  individual  characteristics, 
but  if  only  the  more  important  elements  of  form  be  con- 
sidered, such  as  general  outline  form  and  proportions  of 
width  to  length,  there  are  probably  not  more  than  15  or 
16  important  forms  in  faces  and  teeth.  Fourteen  of  these 
have  been  isolated  and  Trubyte  teeth  harmonious  with 
them  haA^e  been  produced.  They  meet  the  requirements 
of  the  most  exacting  practice. 

There  are  five  distinct  forms  of  the  square  type  of  face. 
They  are  shown  on  page  107. 

106     . 


Face  Forms  and  Tooth  Forms,  Square  Type 


Fie;.   83. 


The  Long  Square 

Narrow  in  proportion  to  length.     Nearly 

straight  and  nearly  parallel  sides. 

Moulds  1C— ID— IE— IF— III. 


The  Medium  Square 

Medium   proportions.     Nearly  straight  and 

nearly   parallel   sides. 

Moulds  2C— 2D— 2E— 2F. 


The  Short  Square 

Short  in  proportion  to  length.     Nearly  straighl 

and  nearly  parallel  sides. 

Moulds  3B—3C— 3D. 


The  Intermediate  Square 

Wide  in  proportion   to  length  and  with    very 

slightly  rounding  outlines.    Rectangular 

in    appearance. 

Moulds  4B— 40— 4E—4H. 


The  Oval 

Long  and  relatively   narrow.     Check    and   jaw 

lines  in  long  sweeping  curves.     Pleasing 

[aces  and  beautiful  teeth. 

Moulds  50— 5D— 5E— 6F— 61 1 . 


107 


Pig.  87. 

The  Typal  Tapering  Face. 

This  form  of  face,  illustrated  and  described  above,  is 
distinguished  from  the  typal  square  and  typal  ovoid  faces 
by  the  more  rapid  convergence  downward  of  the  cheek 
lines  and  their  occasional  concavity.' 

This  frequently  seen  form  of  face  appears  to  have  been 
unrecognized  in  dentistry  until  Dr.  Williams  discovered 
it.  Certainly  no  forms  of  teeth  harmonious  with  it  and 
its  modifications  and  expressive  of  the  character  of  taper- 
ing teeth  were  produced. 

The  five  forms  of  the  tapering  type  are  among  the  most 
frequently  seen  forms  of  faces  and  teeth  and  certainly 
among  the  most  pleasing.  The  faces  are  shown  on  page 
109. 


108 


Face  Forms  and  Tooth  Forms,  Tapering  Type 


i  i 


Fig.   SO. 


The  Typal  Tapering 

Medium  wideormore  in  proportion  to  length. 

Nearly  straight,  converging  sides. 

Moulds  iM— IN— IP— 1R. 


_-     -    -      ..    ^-^\  J 

The  Second  Tapering 

Narrower  in  proportion  to  length  than  the  typal 

form.     Slightly  more  rounding  outlines. 

Moulds  2M—2N—2P. 


(    \    ' 


Third  Tapering 

Wide   in   proportion  to  length.      Noticeablj 

rounding,  converging  sides. 

Moulds  3M— 3N— 3P. 


Fiu.   !H). 


O 


J 


ForiMii  Tapehixi; 

Like  third  tapering  but  narrower  in  proportion 

to  length. 

Moulds  4M— 4N— 4P. 


Fig.  91. 


IJ 


Fig.  02 


Fifth  Tapering 

A  combination  of  the  medium  Bquarc  and 

typal  tapering. 

Moulds  5M     5N    5P— 5R. 

L09 


Mediui 
forehead 

sides  of  head 


Fig.  93. 

The  Typal  Ovoid  Face. 

This  face  is  entirely  unlike  either  of  the  other  types, 
being  wider  in  proportion  to  its  length  and  bounded 
wholly  by  segments  of  circles.  There  is  a  characteristic 
double  curve  in  the  chin  margin,  which  is  reproduced,  in  a 
remarkable  way,  in  the  mesial  surfaces  of  the  upper 
laterals  and  the  distal  surfaces  of  the  upper  centrals. 

Like  the  tapering  type,  this  type  appears  to  have  been 
unknown  to  dentistry  until  discovered  by  Dr.  Williams. 

Faces  of  the  four  forms  in  this  type,  shown  on  page  111, 
are  probably  not  as  numerous  as  those  of  the  other  types, 
but  they  are  often  distinctive  or  pleasing  and  require 
suitable  forms  in  artificial  teeth. 


no 


Face  Forms  and  Tooth  Forms,  <  >void  Type 


Tyiwi.  Ovoid 

Medium  wide  in  proportion  to  length.     Outlines 

in  segments  of  circles. 

Moulds  LW— IX— 1Y. 


Pig.   04. 


Second  Ovoid 

Like  the  typal  ovoid  but  narrower  in  proportion 

to  length. 

Moulds  2U— 2X— 2Y. 


Fig.  95. 


Fig.  90. 


Third  Ovoid 

More  than  medium  vide  in  proportion  t< 
length,  with  converging  convex  sides. 

Moulds  3U— 3W— 3X— 3Y. 


MUM 

Forum  Ovoid 

.ike  the  third  ovoid  bu1  narrower  in  proportion 

to  length. 

Moulds  4U—4W—4X—4Y. 


Fie.  97. 


ill 


kkkkkkkkai 


rig.  os. 

Typal  Forms  in  Natural  Teeth. 

Tt  can  be  shown  that  three  typal  forms  of  upper  centrals 
have  been  common  to  all' races  from  which  we  have  even  a 
dozen  skulls  showing  anterior  teeth,  and  this  without 
relation  to  the  time  in  history,  the  stature,  the  color  or  the 
intelligence  of  the  race. 

One  type  is  square  with  nearly  straight  and  nearly 
parallel  sides ;  the  second  is  tapering  with  nearly  straight 
sides  rapidly  diverging  downward ;  the  third  is  ovoid  with 
all  its  outlines  in  segments  of  circles. 

The  typal  forms  of  teeth  are  so  identical  in  outline  and 
proportions  with  typal  faces  as  to  preclude  any  idea  of 
rare  and  accidental  occurrence,  and  to  amply  support  the 
deduction  of  the  law  on  pages  102  and  103.  This  law  of 
identity  of  form  holds  good  in  fine  specimens  of  the  modi- 
fications of  the  typal  forms. 

Every  other  form  of  teeth  can  be  shown  to  be  a  com- 
bination of  these  forms. 

ISTo  other  typal  form  has  been  found  and  no  form  which 
requires  another  type  to  account  for  it. 

112 


Determining  the  Type  of  Face. 

If  straighl  edges  are  laid  against  the  cheeks,  from  the 
condyles  to  the  angles  of  the  jaw,  the  type  of  face  can  be 
easily  determined  and  the  harmonious  form  of  tooth 
selected.  Tf  the  straight  edges  are  nearly  parallel,  the 
face  is  of  the  square  type  (Class  1.  Trubyte  classification). 
Tf  the  rulers  converge  noticeably  downward,  as  here,  the 
face  is  (it*  the  tapering  type  (Class  II,  Trubyte  classifica- 
tion). If  the  rulers  diverge  downward  from  the  condyles, 
the  face  is  ovoid  (('lass  III,  Trubyte  classification), 


113 


Dimensions  Trubyte  Moulds— UPPERS 


Length  Cen- 

Width 

Width 

Combined 

Mould 

tral  Without 

6  Anteriors 

Full  14 

Bite  and  Shut 

Width  of 

Wo. 

Collar 

Set  up 

Set  up 

of  Central 

Central 

1C 

9.5 

42. 

100. 

8. 

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114 


Dimensions  Trubyte  Moulds — LOWERS 


Length  Cen- 

Width 

Width 

Combined 

Mould 

tral  \\  itboul 

(.  Vnteriors 

hull  14 

Bite  and  Shut 

Width  of 

No. 

Cellar 

Set  up 

Sri  up 

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Central 

f    !C 

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31. 

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115 


TRUBYTE 


A^..    TEETH 


TRUBYTE    TEETH 


yyy  |    ^  vUUi 


*  A  *A.A* 


UUU      ^itu«  ^  3YilUii:  "JLkiiii 


THE    DENTISTS'   SUPPLY    COMPANY,  220     WEST    4  2  nd    STREET.   NEW   YORK,  U.S.A. 


Fig.   100. 


116 


Fig.   101. 

The  Use  or  a  Mould  Guide 

enables  the  dentist  to  compare  the  ontline  form  and  pro- 
portions of  the  entire  line  of  artificial  upper  centrals  with 
the  ontline  form  of  the  face,  and  in  connection  with  the 
Selection  Rim  described  on  page  118,  to  try  the  teeth 
in  the  mouth  and  observe  the  effect. 

If  the  dentist  is  ahle  to  determine  the  Type  and  Form 
of  the  face,  he  can  proceed  to  select  immediately  from  the 
required  type  of  teeth.  Otherwise  he  may  simply  invert 
the  centrals  and  ohserve  which  is  most  like  the  face 

Tn  extensively  modified  faces,  where  selection  is  more 
difficult,  lie  may  compare  the  two  or  three  forms  available 
and  choose  the  mosl   pleasing. 

Tie  may  then  order  teeth  or  select  from  his  stock  by 
mould  number. 


117 


Fig.   102. 

The  Tbubyte  Selection  Rim. 

When  the  teeth  have  been  selected,  the  choice  should 
be  confirmed  by  trying  them  in  the  mouth  to  judge  of  the 
harmony  of  form,  size,  and,  if  the  desired  shade  is  at 
hand,  the  color. 

Trying-in  is  greatly  facilitated  by  the  use  of  the  Selec- 
tion Rim  here  shown  in  use.  It  is  heavily  nickeled  and 
may  be  sterilized  and  filled  with  fresh  wax  for  each 
patient. 

When  natural  lower  teeth  are  in  place,  the  appearance 
of  the  uppers  may  be  contrasted  with  them  by  mounting 
a  roll  of  wax  on  the  back  of  the  Rim  and  setting  it,  with  the 
teeth,  immediately  upon  the  lowers,  with  the  uppers  in 
the  desired  position. 

118 


Fig.    103. 


Shading  in  Artificial  Teeth. 

It  is  impossible  to  make  natural  looking  dentures  if 
the  artificial  anterior  teeth  are  all  of  one  shade,  or  have 
beeii  shaded  without  a  knowledge  of  the  methods  used  by 
nature  to  achieve  her  finest  esthetic  effects. 

In  Figure  103A  good  natural  denture?  are  illustrated. 
In  Figure  103B,  the  same  dentures  are  shown,  bul  made 
all  of  one  shade,  as  must  artificial  teeth  are.  The  uniform 
shading  makes  the  teeth  appear  larger  and  more  promi- 
nent, especially  in  the  hack  of  the  mouth.  This  effect  is 
unavoidable  with  most  artificial  teeth. 

In  line  natural  sets  the  lower  anteriors  arc  deeper  in 
shade  than  the  uppers.  This  is  to  emphasize  the  per- 
spective.    The  laterals  are  generally  a  trifle  darker  than 

119 


*v-  '.;';;!" 


Fig.   104. 

Diagram  of  the  incisal  view  of  upper  and  lower  anteriors. 
Outside  the  teeth,  bands  of  color  showing  the  relative  depths 
of  color  of  the  upper  and  lower  anteriors  in  one  fine  natural 
set.  This  variation  in  color  contributes  greatly  to  the 
beauty  of  the  teeth. 

the  centrals  and  the  lower  cuspids,  the  darkest  of  all  the 
anterior  teeth. 

The  incisal  halves  of  the  upper  centrals  present  the 
lightest  spot  in  both  sets.  The  upper  laterals  are  more 
uniform  in  color  than  the  centrals  and  the  cuspids  darker 
still,  especially  at  the  necks.  The  effect  of  this  shading 
is  to  greatly  emphasize  the  perspective  of  the  rounding 
form  of  the  tooth  row. 

Artificial  teeth  can  be  esthetically  successful  only  when 
the  shading  in  a  set  is  varied  as  it  is  in  fine  natural  teeth. 
The  effort  to  make  up  sets  by  taking  different  shades  is 
only  partly  satisfactory  because  the  shades  are  of  unlike 
characters  and  were  not  meant  to  be  arranged  in  that  way. 

When  artificial  sets  are  properly  shaded  in  the  set,  the 
underbite  of  the  lower  anterior  is  properly  emphasized, 
the  perspective  of  the  rounding  form  of  the  tooth  row  is 
enhanced  as  nature  intended  it  to  be,  the  band  of  color 
shown  by  the  exposed  anterior  teeth  is  more  natural  in 
appearance,  the  bicuspids  and  molars  are  reduced  in  prom- 
inence and  any  slight  error  in  selection  of  shade  is  greatly 
minimized. 

120 


Suggestions  for  the  Selection  of  Shades. 

la  ;i  general  why  ii  may  be  said  thai  the  besl  time  to 
select  tooth  colors  is  between  9  A.  M.  and  3  P.  M.  The 
lighting  of  i  In-  room  should  be  good  but  not  brilliant. 
Brightly  colored  office  furnishings  or  decorations  make 
accurate  matching  impossible.  The  besl  color  for  sur- 
rounding objects  when  matching  shades  is  a  Light  tone  of 
warm  gray  or  brown. 

For  edentulous  patients  select  a  color  which  will  har- 
monize with  the  color  of  the  skin  around  the  orifice  of  the 
mouth.  When  natural  teeth  are  in  the  mouth  these  should 
he  matched  rather  than  the  face. 

Fair  or  white  skinned  people  will  require  much  less 
depth  of  color  in  the  tooth  to  balance  the  depth  of  color 
in  the  face  than  persons  whose  complexion  is  naturally 
highly  modified  by  red  or  yellow  or  darkened  by  exposure 
to  the  sun  or  weather. 

The  skin  of  most  people  will  he  found  to  exhibit  a 
surprising  amount  of  red  if  examined  under  a  separate 
light,  through  a  paper  tube  10  inches  long  and  %  inch  in 
diameter  held  to  the  eve  to  exclude  side  lights.  For  such 
faces  teeth  of  suitable  depth  of  yellow  to  harmonize  with 
the  face  will  be  more  satisfactory  than  any  others. 

A  face  with  clear  or  brilliant  red  coloring  will  require 
teeth  of  clear  yellow,  while  faces  which  have  bilious,  muddy 
yellow  skin  will  require  teeth  thai  are  a  yellow  muddy  hue. 

"Red  and  yellow  or  their  combinations  are  the  basis  of 
color  of  the  skin  of  most  light-skinned  people. 

Dentists  who  are  not  color  experts,  will  do  well  to 
choose  teeth,  for  edentulous  patients,  in  which  the  domi- 
nant color  is  yellow,  ^r  yellow  modified  by  red.  Teeth 
in  which  the  dominant  color  is  blue,  green  or  gray  art1 
very  likely  to  produce  a  disharmony  unless  selected  by 
an  expert  ami  in  any  case  are  rarely  indicated  for  eden- 
tulous pal  ielits. 

121 


A  Table  of  the  Colors  in  the  Twentieth 
Century  Shade  Guide 

Shade  No.  1.     Lightest  shade  in  use.     No  coloring. 

Shade  No.  2.     Trace  of  purple. 

Shade  No.  3.     Trace  of  blue.    Trace  of  yellow.    Lightest  blue. 

Shade  No.  4.     Trace  of  yellow.    Lightest  yellow. 

Shade  No.  5.  Trifle  of  gray  and  trace  of  yellow.  Point  same 
as  No.  4.    Neck  darker. 

Shade  No.  6.  Same  as  No.  4,  with  a  little  gray  in  the  tip. 
Neck  not  so  bright  a  yellow  as  No.  5.    Lightest  gray. 

Shade  No.  7.  Light  yellow.  Darker  than  No.  5,  with  color 
decidedly  stronger  in  neck. 

Shade  No.  8.  Light  yellow.  Tip  darker  than  No.  5  or  No.  7. 
Neck  lighter  than  No.  7,  and  makes  tooth  look  a  straw  color. 
More  uniform  than  No.  7.    Yellow  is  the  only  color  present. 

Shade  No.  9.  A  little  yellow,  a  little  gray,  a  little  pink.  Light 
brown  yellow  neck.    Tip  pink  gray,  follows  No.  11. 

Shade  No.  10.     Gray.    Lighter  than  No.  9.    Darker  than  No.  6. 

Shade  No.  11.  Uniform  gray  throughout.  Neck  grayish  yel- 
low slightly  darker  than  10,  which  it  follows. 

Shade  No.  12.     Grayish  blue.     Follows  No.  3  in  the  blues. 

Shade  No.  13.     Grayish  blue.    Follows  No.  9. 

Shade  No.  14.  Yellowish  gray.  Gray  yellow  neck.  Follows 
No.  13. 

Shade  No.  15.  Pinkish  gray.  Decidedly  darker  and  shows 
more  pink  than  No.  9.  The  other  grays  are  bluish  grays.  This 
follows  No.  14. 

Shade  No.  16.     Yellow.    Follows  No.  8. 

Shade  No.  17.     Greenish  yellow.    Green  tip  and  yellow  neck. 

Shade  No.  18.     Dark  yellowish  gray.    Follows  No.  14. 

Shade  No.  19.     Dark  greenish  yellow.    Follows  No.  17. 

Shade  No.  20.     Brownish  yellow.     Follows  No.  16. 

Shade  No.  21.  Dark  brown  yellow.  Follows  No.  20,  which  it 
is  like,  only  darker. 

Shade  No.  22.     Dark  gray.    Follows  No.  18. 

Shade  No.  23.     Darkest  brown  yellow.     Follows  No.  21. 
.  Shade  No.  24.     Dark  grayish  brown.     Follows  No.  22. 

Shade  No.  25.     Dark  yellowish  brown.     Follows  No.  23. 
Shades  in  order  of  depth  from  light  to  dark. 
Light  Shades,  1-2.     Yellows,  4-5-7-8-16-17-19-20-21-23-25. 
Grays,  6-10-11-9-13-14-15-18-2-24.     Blues,  3-12. 

122 


Surface  Texture  and  Tooth  Shades. 

Dentists  who  wish  to  make  fine  prosthetic  restorations 
should  avoid  using  teeth  with  such  smooth  labial  surfaces 
thai  they  look  glassy.  While  the  labial  surfaces  of  many 
natural  teeth  have  been  worn  smooth  by  lip  action,  the 
finest  teeth  present  labial  surfaces  with  slighl  irregulari- 
ties, as  though  the  enamel  had  been  deposited  in  waves. 
These  irregularities  diffuse  the  light  reflected  by  the 
teeth  and  soften  both  the  high  lights  and  the  shadows.  The 
result  is  that  the  entire  tooth  has  a  soft  and  pleasing 
color. 

The  artificial  teeth  of  the  past  have  presented  either 
very  smooth  labial  surfaces  or  depressions  like  those  re- 
sulting from  defective  calcification.  The  smooth  surfaces 
have  collected  light  rather  than  diffused  it  and  have  ex- 
hibited small,  localized  strong  high  lights  and  deep 
shadows.  The  high  lights  being  brighter  than  the  color 
of  the  tooth,  and  the  shadows  deeper  than  that  color,  have 
made  it  impossible,  in  certain  cases  or  certain  lights,  to 
place  artificial  teeth  beside  natural  teeth  and  have  them 
indistinguishable,  however  carefully  the  shade  was  chosen. 

When  Trubyte  teeth  were  produced,  this  subject  of  dif- 
fusion of  light  was  given  very  careful  consideration,  and 
after  much  experimenting  to  develop  a  method  of  mould- 
making  which  permitted  the  production  of  labial  surfaces 
with  satisfactory  irregularities  to  diffuse  the  light,  Tru- 
byte teeth  were  brought  out  with  such  surfaces. 

Three  of  the  great  factors  in  shade  selection  are  thus 
placed  in  a  favorable  position  before  the  dentist,  satis- 
factory shades  from  which  to  select;  a  variation  of  shade 
in  the  set  and  between  uppers  and  lowers  which  achieves 
the  proper  perspectives;  and  tooth  surfaces  which  diffuse 
the  light  as  do  the  tinest  natural  teeth. 

123 


Part  III 

Measuring  Habitual 
Masticating  Movements 


Why  It  Is  Worth  While  to  Reproduce  Jaw 
Movements. 

Because  if  the  dentist  can  foresee  the  conditions  under 
which  the  dentures  will  operate  in  any  mouth,  he  can 
achieve  stability,  comforl  and  efficiency  in  those  dentures. 

It  is  probable  that  the  permanent  natural  teeth  deter- 
mine the  habitual  movements  of  the  jaw,  and  there  can  he 
no  question  that  these  movements  determine  the  bony 
formations  in  the  fossae  and  condyles  and  often  alter  them 
extensively. 

The  natural  teeth  are  rarely  lost  all  at  once  or  evenly 
on  both  sides  or  both  jaws.  With  the  uneven  loss  of  teeth 
the  jaw  movements  on  the  two  sides  change,  sometimes  in 
great  degree.  The  jaw  is  often  incapable  of  movements  on 
one  side  which  it  habitually  performs  on  the  other. 

When  all  the  natural  teeth  are  lost,  the  only  guides  as 
to  what  the  habitual  movements  were,  are  the  records  of  the 
habitual  jaw  movements.  If  these  can  be  recorded  and  re- 
produced in  an  articulator,  the  teeth  can  be  so  arranged 
that  when  they  are  placed  in  the  mouth,  the  jaw  can  go 
right  on  with  the  movements  to  which  it  is  accustomed!,  the 
dentures  will  not  lie  dislodged,  and  the  teeth  will  oppose 
each  oilier  in  the  manner  essential  to  trituration. 

Any  other  course  requires  the  adoption  of  an  arbitrary 
set  of  movements  for  the  jaw,  the  arrangement  of  teeth 
to  harmonize  with  them,  and  the  error!  to  force  the  jaw  to 
adopt  1 1 10  arbitrary  movements,  with  the  necessary  changes 
in  bony  formation  and  muscular  action,  which  in  advanced 
age  is  impossible. 

"Custom-made"  dentures,  that  is.  those  made  to  fit  the 
individual  patient  as  clothes  fit  the  individual  form,  are 
so  much  move  satisfactory  to  patients  and  dentists  as  to 
fully  justify  the  necessary  procedure. 

125 


Interferences  that  Prevent  Correct  Records. 

It  is  impossible  to  take  correct  records  of  the  habitual 
jaw  movements,  if  the  heel  of  either  impression  is  so 
bulky  as  to  interfere  with  natural  free  movements  of  the 
jaw. 

If  the  impression  material  over  the  upward  inclines  of 
the  lower  ridge  is  too  thick,  it  may  come  into  contact  with 
the  material  over  the  tuberosities  of  the  upper  jaw  which 
may  also  be  too  bulky.  These  improper  contacts  may 
cause  pain.  The  patient  should  be  instructed  to  report 
even  slight  sensations  of  pain  or  any  feeling  that  the  free 
movement  of  the  mandible  is  hindered. 

To  relieve  such  contacts,  trim  the  bite  rim  or  impres- 
sions as  thin  as  may  be  necessary  but  without  cutting 
through  the  impressions  or  altering  their  margins.  It  is 
often  necessary  to  cut  away  portions  of  the  tray. 

If  the  impression  cannot  be  trimmed  thin  enough  to 
avoid  interference,  adjust  the  Condyle  Path  Register  as 
described  for  Figure  124.  Lock  the  bites  together  by  the 
method  described  for  Figure  126,  remove  them  from  the 
mouth  and  dismiss  the  patient.  Pour  casts  and  mount 
them  in  the  articulator,  using  the  technic  given. 

Remove  the  upper  impression  from  the  cast,  leaving 
the  lower  in  place.  Make  a  baseplate  of  Dentsply  Base 
Plate  Composition  for  the  upper.  Make  a  compound  bite 
rim  on  this  baseplate  and  fit  it  to  the  flat  surface  of  the 
Horseshoe  Plate,  with  the  incisor  guide  pin  in  place.  In 
the  same  manner  remove  the  lower  impression  and  adapt 
a  baseplate  to  the  lower  ridge,  make  a  compound  bite  rim 
and  fit  it  to  the  upper  bite  rim. 

Attach  the  Horseshoe  Plate  to  the  block  on  the  Condyle 
Path  Register,  open  the  articulator  and  allow  the  Horse- 
shoe Plate  to  move  on  the  top  of  the  lower  bite  rim  and 
bring  the  points  of  the  horizontal  pencils  to  be  opposite 
the  heads  of  the  condyle  pins.  Then  press  down  on  the 
Horseshoe  Plate  so  as  to  make  an  imprint  of  its  pins  on 

126 


the  occlusal  surface  of  the  lower  bite  rim.  Remove  the 
Face  Bow  and  attach  the  Horseshoe  Plate  to  the  lower  bite 
rim  using  the  technic  described  for  Figure  L09. 

IIcni  the  occlusal  surface  of  the  upper  bite  rim  to  a 
very  shallow  depth  and  close  ii  upon  t lie  Horseshoe  Plate  to 
equalize  biting  pressure.  Trim  the  occlusal  surface  of  the 
tipper  bite  rim  so  thai  it  is  smooth.  When  the  patienl 
returns,  take  records  described  in  following  pages, 


Fig.   103. 

A  Horseshoe  Plate. 

B-B  Wings  of  Condyle  Path  Register. 

D  Gooseneck  and  stand  for  supporting  Register  when  mounting  casts, 

E  Incisor  Path  Marker. 

F-F  Uprights  from  w  Lngs  supporting  pencil.-. 

G-G  Screws,  which,  when  turned  move  the  wings  horizontally. 

H  Setscrew  01  Rectangular  Blocks  of  Register. 

1-1  Milled  tracks  on  which  wings  are  moved. 

.7  One  of  the  two  horizontal  pencils. 

K  One  of  the  two  vertical  pencils. 


Condyle  Path   Registeb  and  A.ccess6hess. 

In  this  illustration  the  Condyle  Path  Register  is  shown 
attached  to  the  Horseshoe  Plate  supported  by  the  black 
gooseneck  and  its  stand.  The  gooseneck  and  supporting 
frame  are  used  only  when  mounting  the  casts  in  the  artic- 
ulator.    The  set-screw  locks  the  Register  to  the  gooseneck. 

127 


The  Condyle  Path  Register  is  used  to  make  tracings  of 
two  inclinations  of  the  condyle  path  and  also  as  a  Face 
Bow.  It  has  a  central  rectangular  block  in  which  are  two 
holes  to  receive  the  pins  of  the  Horseshoe  Plate  "A"  and 
through  which  passes  a  cylindrical  transverse  rod  that 
has  at  each  end  the  geared  tracks  "I"  on  which  the  wings 
"B"  of  the  register  may  be  moved  inward  and  outward 
at  will,  by  turning  the  milled  nuts  uGr"  to  bring  the  ver- 
tical pencil  "K"  or  the '  horizontal  pencil  "  J"  to  the 
desired  relation  to  the  sides  of  the  face  over  the  head  of 
the  condyles.  The  vertical  cylindrical  rods  "FF"  may  be 
raised  or  lowered  to  help  in  adjusting  the  pencils  "J" 
and  "K"  and  locked  by  turning  the  set-screw  shown  just 
below  the  arrow  leading  from  the  letter  "F." 

When  the  lower  jaw  is  moved  from  right  to  left  and 
the  horizontal  pencil  points  are  correctly  set  they  can 
make  a  tracing  of  the  descending  inclination  of  the  con- 
dyle path  on  a  card  held  in  a  vertical  position  against 
the  side  of  the  face. 

The  vertical  pencil  points  "K"  make  tracings  on  the 
glass  tabs  of  the  lateral  path  register  shown  in  illustra- 
tion which  indicate  the  lateral  inclination  of  the  condyle 
path. 

The  Incisor  path  recording  instrument  "E"  when  at- 
tached to  the  upper  bite  rim,  in  the  median  line  is  used 
to  trace  a  record  of  the  incisor  path  on  a  blackened  area 
on  the  front  of  the  Horseshoe  Plate  "A"  which  is  attached 
to  the  occlusal  surface  of  the  lower  bite  rim.  This  record 
assists  in  correctly  adjusting  the  articulator  as  well  as  in 
determining  when  the  bite  is  correct. 


128 


Fig.   10(5. 

Locating  the  Heads  of  the  Condyles. 

It  is  essential  to  that  technic  which  follows  that  the 
location  of  the  centers  of  the  heads  of  the  condyles  should 
he  indicated  upon  the  face  in  such  way  that  the  Condyle 
Path  Register  or  the  Snow  Face  Bow  can  lie  properly 
adjusted. 

These  locations  can  be  most  easily  made  by  the  use  of 
a  flexible  ruler  which  should  be  placed  againsl  the  side 
of  the  face  so  that  its  lower  border  extends  from  the 
upper  margin  of  the  external  auditory  meatus  to  the  outer 
corner  of  the  eye,  as  shown  above.  With  an  Eastman 
negative  retouching  pencil  or  a  soft  lead  pencil,  draw  a 
line  forward  along  the  lower  border  of  the  ruler  for  about 
%  of  an  inch  from  the  anterior  margin  of  the  meatus. 
Draw  a  line  vertically  across  this  one  aboul  \b  inch  from 
the  anterior  margin  of  the  meatus.  The  intersection  of 
these  lines  will  usually  locate  the  center  of  the  head  OJ 
the  condyle.      Mark  the  location  of  the  center  of  the  head 

of  the  other  condyle  in  the  same  way, 


V29 


Fig.  106A. 

Locating  the  Hoeseshoe  Plate,  Part  II. 

Release  the  hold  upon  the  Condyle  Path  Register.  Stand 
in  front  of  the  patient  and  part  the  lips,  see  that  about  y2 
inch  of  the  Horseshoe  Plate  is  visible  and  note  whether  the 
points  of  the  recording  pencils  can  be  adjusted  to  reach  the 
crosses  made  over  the  centers  of  the  heads  of  the  condyles. 

If  the  relations  are  fonnd  to  be  satisfactory,  instruct 
the  patient  to  bite  forcibly  on  the  Horseshoe  Plate  and  force 
the  pins  on  its  under  surface  into  the  bite  rim.  The  im- 
pressions the  pins  make  will  be  used  later  to  correctly  lo- 
cate the  Horseshoe  Plate  for  attaching  the  bite  rim. 

130 


Fie:.  107. 


Withdrawing  the  Condyle  Path  Register. 

Support  the  distal  end  of  the  right  wing  of  the  Condyle 
Path  Register  with  the  left  hand.  Place  the  thumb  and 
two  lingers  of  the  right  hand  on  opposite  sides  of  the  an- 
terior part  of  the  Horseshoe  Plate  and  pinch  the  thumb  and 
fingers  together  so  that  they  will  slide  forward  on  the  con- 
verging margins  of  the  plate.  If  this  pressure  is  contin- 
ued after  the  thumb  and  fingers  come  into  contact  with 
the  center  block  of  the  Condyle  Path  Register,  this  block 
will  be  forced  off  the  Horseshoe  Plate  without  discomfort 
to  the  patient. 

Lay  the  Condyle  Path  Register  aside  and  remove  the 
upper  impression,  and  the  lower  impression  with  the 
Horseshoe  Plate  attached. 


131 


Fig.   10S. 

Attaching  the  Horseshoe  Plate  to  the  Bite 

Rim. 

Dry  the  occlusal  surface  of  the  lower  hite  rim  and  all 
of  the  Horseshoe  Plate.  Seat  the  pins  of  both  sides  of  the 
Horseshoe  Plate  in  the  imprints  in  the  occlusal  surface  of 
the  bite  rim,  as  here  shown.  Direct  a  mouth  blow  pipe 
name  from  an  alcohol  lamp  on  the  occlusal  surface  of  the 
Horseshoe  Plate  at  the  point  "B,"  and  heat  carefully  until 
the  pins  can  be  pressed  all  the  way  down.  Do  not  overheat 
or  the  plate  may  sink  into  the  bite  rim  and  destroy  the 
plane  of  occlusion. 

Partly  chill  the  side  on  which  the  pins  are  down  and 
heat  the  opposite  side  and  press  the  pins  down  in  like 
manner.     Thoroughly  chill  the  entire  rim. 


132 


Fig    109. 

Equalizing  Biting  Strain  on  the  Bite  Rims. 

The  seating  of  the  Horseshoe  Plate  may  have  destroyed 
the  equal  biting  stress  on  the  opposite  sides  of  the  bite  rims. 
Heat  the  occlusal  surface  of  the  upper  Lite  rim  with  a 
mouth  blow  pipe  flame  from  an  alcohol  lamp  to  a  depth 
of  about  1/32  of  an  inch.  Equalize  the  temperature  in 
hot  water,  place  in  the  mouth,  (lie  lower  impression  and 
Horseshoe  Hate  being  in  position,  and  cause  the  patient 
to  touch  the  tip  of  the  tongue  to  the  centre  of  the  hack  of 
tlit-  hard  palate,  close  and  swallow.  When  the  upper  bite 
rim  is  hard,  remove  it  and  trim  the  margins  of  the  oc- 
clusal surface  until  it  shows  no  imprints  of  the  edges  of 
the  Horseshoe  Plate. 

If  the  biting  pressure  is  equal  all  around,  it  will  be 
possible  for  the  patient  to  snap  the  rims  together  with  a 
sharp,  definite  sound.  Unequal  pressure  will  cause  a 
mullled,  prolonged  sound. 


i:::; 


Fig.   110. 


Adjusting  the  Horizontal  Pencils. 

Smear  the  occlusal  surface  of  the  Horseshoe  Plate  with 
cocoa  butter.  Replace  the  central  block  of  the  Face  Bow 
on  the  projecting  pins  of  the  Horseshoe  Plate,  so  that  the 
block  touches  the  point  of  the  plate.  Move  the  right  wing 
of  the  Condyle  Path  Register  until  the  point  of  the  hori- 
zontal pencil  touches  the  face.  Loosen  the  lock  nut  and 
move  the  horizontal  pencil  of  one  side  until  its  point  is  at 
the  intersection  of  the  lines  over  the  head  of  the  condyle. 
Lock  the  pencil  in  this  position.     Adjust  the  other  pencil. 

Special  care  must  be  used  to  lock  the  pencil  holders 
firmly  or  they  may  move  slightly  and  confuse  the  records. 

Move  the  wings  outward  until  the  points  of  the  pencils 
are  about  Va  inch  from  the  face. 


134 


Fig.    HI. 

Registering   the  Descending    Inclination   of 
the  Condyle  Path. 

A  device  suggested  by  Dr.  Zurbrigg  is  very  convenient 
for  holding  the  card  in  recording  the  descending  inclina- 
tion of  the  condyle  paths.  It  consists  of  two  card  holders 
and  a  connecting  wire.  Each  card  holder  is  made  by  fold- 
ing a  shoe!  of  brass  and  soldering  a  sleeve  on  one  side  of  the 
fold.  Platinoid  wire  of  sufficient  length  to  go  over  tho 
head  as  shown  is  bent  near  the  ends  to  lit  into  the  sleeves. 

Insert  a  card  into  the  right  holder  and  support  it  as 
shown  so  that  its  lower  margin  parallels  the  wing  of  the 
Condyle  Path  Uegister.  Move  the  wing  of  the  Condyle 
Path  Register  toward  the  face  until  the  pencil  presses 
against  the  card  with  light  spring  pressure.  Place  the 
finger  againsl  the  card,  just  in  front  of  the  upper  part 
of  the  ear,  and  hold  it  firmly  against  the  fare. 

Cause  the  patient  to  move  the  jaw  from  right  to  left 
with  the  bite  rims  lightly  in  contact.  The  pencil  records 
the  descending  inclination  of  the  condyle  path  habitual  to 
the  patient.    Make  records  for  both  sides. 


> 


A  B 


Correct  and  Incorrect  Descending  Inclina- 
tion Record. 

If  the  record  of  the  descending  inclination  exhibits 
several  parallel  lines,  as  shown  at  "A"  it  is  probable  that 
the  card  has  been  gradually  raised  by  the  operator  while 
the  record  was  being  made.  If  the  record  is  of  the  char- 
acter shown  at  UB"  the  patient  is  probably  dropping  the 
jaw  slightly  as  it  moves  from  side  to  side,  or  there  may  be 
interference  between  material  of  the  upper  and  lower  im- 
pression or  between  the  upper  impression  and  the  ramus. 
This  causes  the  lower  impression  to  tip  a  little  and  the 
Condyle  Path  Register  and  the  recording  pencil  tip  with 
it  resulting  in  the  characteristic  marks  here  shown. 
=>  When  the  pencil  starts  from  the  point  of  "rest  and  makes 
a  forward  and  return  movement  in  the  same  path  as  at 
"C",  the  record  is  accurate. 

If  any  doubt  exists  as  to  the  accuracy  of  the  records, 
raise  the  card  half  an  inch,  keeping  its  lower  margin  par- 
allel to  the  wing  of  the  register,  and  make  a  duplicate 
record.  This  may  be  done  a  third  time  if  desired.  Remove 
the  register  as  described  for  Figure  107. 


136 


Fig.  113. 

Attaching  the  Incisor  Path  Marker  to  the 
Impression. 

Invert  llie  upper  impression  and  hold  ns  shown.  Hold 
the  incisor  path  marker  with  the  pin  released  between  the 
thumb  and  finger  and  heat  the  points  of  the  pins  in  the 
flame,  but  not  until  the  marker  becomes  uncomfortable  to 
hold.  Press  the  points  of  the  pins  against  the  labial  sur- 
face of  the  upper  impression  so  that  the  recording  point 
and  its  holder  will  be  in  the  median  line.  Reheat  the  pins 
and  attach  the  marker  firmly  in  position. 

The  vertical  position  of  the  marker  should  be  such  that 
when  the  spring  governing  the  marking  point  is  released, 
only  the  cone  of  the  marker  projects  below  the  level  of 
the  incisal  edge  when  the  bite  rim  is  in  the  proper  po- 
sition. 


i.'.r 


Fig.  114. 

Blackening  the  Hoeseshoe  Plate. 

Roll  cotton  on  the  end  of  a  toothpick  or  match,  dip  in 
oil  of  cloves,  light  it,  and  with  the  smoke  blacken  the  an- 
terior part  of  the  occlusal  surface  of  the  Horseshoe  Plate. 

Lay  a  ball  of  Dentsply  Base  Plate  Wax  about  1/16 
inch  in  diameter  at  the  point  of  the  Horseshoe  Plate  and 
with  a  very  hot  and  clean  spatula,  or  a  mouth  blow  pipe 
flame,  flow  it  over  the  black  surface  as  far  back  as  the 
first  notch  on  each  side.  This  wax  film  is  merely  a  pro- 
tection for  the  lampblack  and  should  *be  as  thin  as  pos- 
sible. 

Wipe  away  the  uncovered  lampblack. 


138 


Pig.  115. 

Taking  the  Incisor  Path  Record. 

Lock  the  pin  of  the  Incisor  Path  Marker  in  the  raised 
position.  Place  the  upper  and  lower  impressions  in  the 
mouth.  Release  the  pin  and  have  the  patient  move  the 
jaw  from  side  to  side  with  the  bite  rims  lightly  in  contact 
aboul  a  dozen  limes,  and  then  move  from  front  to  hack. 
These  movements  should  cut  the  wax  from  a  well  defined 
V  shaped  area,  with  a  pointed  front. 

[f  the  record  does  not  present  a  sharp  point,  an  abnor- 
mal habit  of  holding  the  jaw  may  be  suspected.  Patients 
long  without  posterior  teeth  may  hold  the  jaw  forward  of 
the  normal  resl  position.  A  correct  record  may  usually 
be  had  from  such  patients  by  causing  them  to  open  the 
mouth,  touch  the  tip  of  the  tongue  to  the  rear  of  the  center 
of  the  vault  and  close  with  the  tongue  in  that  position,  and 
then  move  the  jaw  to  one  side  and  hold.  Repeat  the  open- 
ing, the  tongue  placing,  and  the  closing,  and  have  the  pa- 
lieni  move  to  the  other  side.     Repeal  several  times. 


139 


Correct  and  Incorrect  Incisor  Path  Records. 

(Illustrations  on  page  following.) 

If  the  lower  jaw  is  protruded  during  record  taking  so 
that  the  condyles  are  forward  of  their  normal  position 
for  mastication,  the  marker  will  trace  an  indefinite  path, 
with  a  rounded  point,  like  that  shown  at  "A"  in  Figure 
116.       Such    a    record    is    incorrect    and    of    no    value. 

Normal  masticating  movements  give  the  sharp  pointed 
form  of  record  shown  in  "B"  and  "G."  We  believe  that 
if  there  is  no  movement  of  the  impressions  during  record 
taking,  there  is  no  exception  to  this  statement.  When  the 
lower  jaw  is  very  flat,  hold  the  lower  impression  in  place 
during  record  taking. 

The  record  in  "B"  shows  the  usual  extent  of  movement. 
That  in  "C"  is  from  a  patient  with  unusually  extensive 
lateral  and  protrusive  movements. 

If  the  record  on  one  side  of  the  median  line  is  much 
shorter  than  on  the  other,  examine  the  upper  impression 
over  the  tuberosities  on  the  side  opposite  the  short  record. 
It  may  be  that  the  impression  in  this  region  is  so  thick 
that  it  interferes  with  the  free  movement  of  the  jaw.  See 
the  reference  to  this  subject  on  page  126. 

Incisor  path  records  are  important  not  only  for  making 
possible  the  reproduction  of  the  individual  jaw  movements 
in  the  articulator,  but  they  constitute  the  only  exact  method 
of  determining  when  the  lower  jaw  is  in  correct  relation 
to  the  upper  for  locking  the  bite  rims  together.  When 
the  lower  jaw  is  at  rest  with  the  point  of  the  marker  at 
the  apex  of  a  record  as  at  "D,"  Figure  116,  the  upper 
and  lower  bites  are  in  correct  antero-posterior  and  lateral 
relations. 

If,  when  the  jaw  is  at  rest,  the  point  of  the  marker 
touches  the  record  at  "E"  the  bites  are  in  correct  lateral 
relations,  but  the  jaw  is  protruded. 

If,  with  the  jaw  at  rest,  the  point  of  the  marker  is  at 
"F,"  the  bites  are  in  correct  antero-posterior  relations  but 
incorrect  lateral  relations. 

140 


Correct  and  Incorrect  Lncisob  Path  Records. 

Dentists  will  do  well  to  learn  to  look  on  this  record  as  a 
picture  which  shows  whether  the  bite  plates  are  in  correct 
relation.     Lock  the  marking  pin  in  the  raised  position. 

For  ;i  description  of  these  records  and  their  significance, 
see  the  preceding  page. 

in 


[11111 


Fig.  117. 

Drawing  Base  Lines  for  the  Lateral 
Inclination  Records. 

Lay  the  Lateral  Path  Register  on  the  bench  with  the 
ground  glass  side  upward.  Place  a  rule  across  both  glasses 
as  shown.  Hold  it  in  one  position  and  draw  the  line 
shown  at  "A"  about  ^  inch  from  the  narrow  end  of  the 
glasses.  The  line  on  one  glass  is  a  continuation  of  that  on 
the  other  and  both  lines  are  approximately  parallel  to  the 
square- bar  at  the  back  of  the  register. 

About  14  inch  from  the  line  "A"  toward  the  wide  ends 
of  the  glasses,  draw  the  line  "B,"  parallel  to  the  line  "A." 

These  lines  are  to  serve  as  starting  points  from  which 
to  make  records  for  determining  the  lateral  inclination  of 
the  condyle  path  and  are  called  base  lines. 


143 


Fig.  118. 

Adjusting  the  Vertical  Pencils. 

Place  the  Condyle  Path  Ilegister  in  position  on  the 
Horseshoe  Plato.  Loosen  the  lock  nut  holding  the  recording 
pencil  tin  one  side.  Turn  the  vertical  pencil  toward  the 
lace  Move  the  wing  of  the  Condyle  Path  Register  inward 
u  ni  1 1  i  he  ] mi iii  (il  the  vertical  pencil  is  level  with  and  oppo- 
site the  intersection  of  the  lines  over  the  head  of  the  con- 
dyle Loch  the  pencil  so  firmly  in  position  thai  it  cannot 
be  moved  during  record  taking.  Adjust  the  pencil  on 
the  opposite  side  in  the  same  way.  Move  the  wings  of  the 
Condyle  Path  Register  outward  until  the  vertical  pencils 
are  aboul  1  •'«  inch  from  the  face,  as  here  shown. 

143 


Fig.  110. 


Holding  the  Lateral  Path  Register,  Part  I. 

Have  the  patient  sit  on  a  low  stool  or  depress  the  chair 
and  drop  the  headrest.  Stand  directly  behind  the  patient 
with  the  arms  free  from  the  body.  Grasp  the  Register  with 
both  hands  as  here  shown  and  carry  it  from  above  down- 
ward and  backward  about  the  head  until  the  glasses  are 
above  the  points  of  the  pencils  but  not  in  contact  with  them. 
Place  the  ends  of  the  second  fingers  in  the  external  audi- 
tory canals.  The  arms  of  the  Register  should  rest  across 
the  bases  of  the  thumbs  and  the  outer  joints  of  the  middle 
fingers.  The  index  fingers  rest  on  top  of  the  arms  of  the 
Register  with  just  enough  pressure  to  prevent  the  Register 
slipping  forward.  The  third  fingers  rest  on  the  base  of  the 
skull  and  the  thumbs  are  placed  as  shown. 

144 


Pig.  120. 

Holding  the  Lateral  Path  Register,  Part  II. 

Hold  the  Register  as  described  and  bring  the  two  pos- 
terior base  lines  in  contact  with  the  points  of  the  pencils. 
Slope  the  glasses  downward  and  forward  at  about  the 
same  inclination  as  the  tracings  of  (lie  descending  inclina- 
tion of  the  condyle  paths.  The  glasses  should  "float"  upon 
the  pencil  points  so  that  they  may  follow  any  change  in 
elevation  of  the  pencils  as  they  move.  If  the  glasses  rest 
heavily  on  the  pencils  during  the  movement,  the  leverage 
may  be  sufficient  to  dislodge  the  lower  impression  from  the 
ridge  and  give  incorrect  records. 

Patients  show  a  strong  tendency  fo  move  the  head  dur- 
ing the  talcing  of  ibis  record.  Do  not  try  to  bold  the  bend 
still;  instruct  the  patient  to  resist  ibis  tendency  and  poise 
the  bunds  and  Register  so  that  they  may  move  with  tin- 
head  as  nearly  as  possible.  It  is  sometimes  advantageous 
to  have  ;in  assistanl  bold  the  lower  impression  firmly  in 
place  wbi le  ibis  record  is  made. 

145 


Fig.  121. 

Recording  the  Lateral  Inclination. 

Instruct  the  patient  to  keep  the  bite  rims  in  contact 
with  very  light  pressure  and  move  the  jaw  slowly,  first 
to  the  right  and  then  to  the  left.  This  movement  to  the 
right  should  make  a  long  tracing  on  the  left  glass  in  front 
of  the  base  line  which  slopes  downward  and  inward  as  here 
shown,  and  a  shorter  tracing  on  the  right  glass  continued 
back  of  the  base  line,  either  as  a  continuation  of  the  for- 
ward inclination  on  that  side  or  with  a  different  slant,  and 
vice  versa. 

Both  lateral  records  are  taken  at  the  same  time,  while 
one  descending  inclination  is  recorded  at  a  time. 

The  pencils  must  start  on  the  base  line  and  finish  on 
the  base  line  with  the  jaw  in  the  rest  position.  Any  other 
position  of  the  pencils  with  the  jaw  at  rest  indicates  that 
the  Lateral  Path  Kegister  has  moved  and  that  the  record  is 
valueless.  Other  records  may  be  taken  starting  at  the  base 
lines  in  front  of  the  two  just  used. 

14C 


Fig.  122. 


Correct  and  Incorrect  Lateral  Paths. 

A  lateral  path  record  which  is  incorrect  in  two  impor- 
tant particulars  is  shown  at  "A"  in  Number  2.  The  reg- 
ister moved  enough  during  the  taking  of  the  record  so  that 
when  the  jaw  was  returned  to  a.  position  of  rest  the  pencil 
was  :ii  "D"  instead  of  on  the  hase  line.  The  loop  in  the 
record  shows  rhat  the  patient  made  the  record  with  jaw 
protruded,  or  that  the  lower  impression  moved  on  the 
ridge,  perhaps  because  the  glasses  pressed  too  heavily  on 
the  pencils  or  the  lower  impression  was  not  stable  on  the 
ridge,  or  because  of  an  interference  described  on  page  1-7. 
Discard  such  a  record  and  make  a  new  one. 

The  loop  at  "A,"  Number  1,  shows  that  the  patient  pro- 
truded the  jaw  during  al  leasl  one  cycle  of  jaw  movement. 

At  "B"  in  Number  1  is  shown  a  good  record  from  a  pa- 
tient who  has  worn  artificial  dentures  for  a  long  time.  Con- 
trol of  the  jaw  movements  has  been  losl  to  such  an  extent 
that  the  pencil  did  not  move  continuously  in  the  same  line, 
but  moved  in  parallel  lines. 

Ai  "B"  in  Number  2  is  shown  a  correct  record  from  a 
patienl  who  has  recently  lost  the  natural  teeth  and  who-, 
jaw  movements  have  not  become  indefinite  as  a  result  oi 
wearing  improperly  made  dentures. 

it: 


Fig.  123. 

Adjusting  the  Condyle  Path  Register  and 
Removal. 

Make  sure  that  the  point  of  the  incisor  path  marker  pin 
is  at  the  point  of  the  incisor  path  tracing. 

Return  the  points  of  the  horizontal  pencils  to  the  po- 
sition in  Figure  106A,  in  contact  with  the  tissues  over  the 
condyles,  and  lock  them  firmly  in  position  so  that  they 
cannot  be  disturbed  during  subsequent  manipulation. 

With  an  Eastman  negative  retouching  pencil  make  a 
mark  on  each  wing  of  the  face  bow  directly  at  the  end  of 
the  milled  tract,  while  the  pencils  are  in  position  as  shown. 

Move  both  wings  away  from  the  face  so  that  the  pencils 
will  "clear''  and  remove  the  face  bow  from  the  Horseshoe 
Plate  in  the  manner  described  for  Figure  107. 

148 


Pig.  124. 

Correcting  Lack  of  Fit  in  the  Impression. 

Hoar  the  end  of  a  tracing1  stick  in  the  bnnsen  flame  until 
it  becomes  almost  fluid.  Trace  the  softened  compound 
mi  the  area  of  the  impression  which  is  defective  as  shown 
at  "A."  Dip  this  section  of  the  impression  quickly  into 
hot  water,  remove,  seal  the  impression  on  the  ridge  and 
chill  the  compound  in  position  until  it  is  set. 

While  a  little  moisture  remains  on  the  palatal  surface 
of  the  impression,  direct  a  mouth  blowpipe  flame  from  an 
alcohol  lamp  against  the  margin  of  the  added  compound 
and  the  adjacent  area  of  the  impression  as  shown  at  "B." 
1 1  cat  this  area  to  a  flowing  stage  as  quickly  as  possible 
without  burning  the  compound.  Dip  the  impression  in  hot 
water,  quickly  remove  and  place  in  position  in  the  mouth. 
When  the  compound  is  set,  remove.  With  a  sharp  knife 
trim  away  the  compound  which  projects  beyond  the  margin 
as  originally  determined,  as  shown  at  "C." 

A  second  method  of  correcting  errors  due  to  lack  of  im- 
pression material  in  the  base  impression  is  as  follows: 
Have  the  lower  impression  in  place  in  the  mouth.  Heat 
the  end  of  a  tracing  stick  till  fluid  and  add  a  suf- 
ficient amount  of  compound  to  the  defective  portion  of  tin1 
impression  to  till  up  the  defect.     Chill  the  impression  and 

149 


Correcting  Lack  or  Fit  in  the  Impression. 
Continued. 

addition  in  cold  water.  Heat  the  added  material  and  the 
surface  of  the  impression  adjacent  to  it  with  the  mouth 
blowpipe  flame  and  reduce  the  temperature  of  the  hot  ma- 
terial by  immersing  in  the  hot  water  and  instantly  remov- 
ing it.  Place  the  impression  in  the  mouth,  have  the  patient 
close  and  suck.  Chill  the  impression  thoroughly  in  place 
and  remove. 

This  method  will  usually  yield  satisfactory  results  at  the 
first  insertion. 

The  marginal  flanges  of  the  upper  impression  are  some- 
times deficient  in  adaptation,  due  to  difficulty  encountered 
in  carrying  the  material  above  the  tuberosity  to  a  proper 
height  while  taking  the  base  impression.  Other  portions 
of  the  margins  of  the  flanges  are  also  subject  to  faulty 
adaptation  if  the  impression  material  was  too  cold  when  the 
base  impression  was  taken.  Defects  such  as  this  may  be 
corrected  by  making  additions  of  compound  to  the  imper- 
fect portion  of  the  impression  with  a  tracing  stick. 

In  using  the  tracing  stick  for  the  first  technic  given,  care 
must  be  exercised  to  use  all  the  speed  possible1  in  the  opera- 
tion after  the  hot  material  is  added  to  the  impression.  If 
much  time  elapses  between  the  tracing  of  the  hot  material 
on  the  flange  and  the  final  placing  and  seating  of  the  im- 
pression on  the  ridge,  the  flange  will  absorb  heat  from  the 
tracing  and  become  sufficiently  softened  to  bend  in  the 
process  of  seating  the  impression  creating  another  type  of 
error  difficult  both  to  detect  and  correct  and  frequently 
serious  enough  to  make  necessary  the  repetition  of  steps  of 
impression  taking  up  to  the  point  where  the  tracing  com- 
menced. 

The  first  technic  that  follows  is  usually  employed  when 
retention  is  defective  before  the  bite  rim  is  added  to  the 
lower ;  the  second  is  used  after  the  bite  rims  are  built  on 
the  impression. 

150 


Pig.  125. 

Peepabing  the  Bite  Rims  for  Locking. 

Smooth  the  buccal  surfaces  of  the  upper  and  lower  hite 
rims  for  an  inch  back  of  the  cuspids,  on  both  sides,  so  that 
there  are  no  undercuts  or  indentations.  If  any  traces  of 
the  notches  cut  on  the  occlusal  surfaces  of  the  upper  bite 
rims  remain,  fill  them. 

Deepen  the  vertical  lines  made  across  the  buccal  sur- 
faces of  both  bite  rims,  l/o  inch  back  of  the  cuspids,  into 
irregular  V-shaped  notches  as  shown  above.  Cut  two  rect- 
angular pieces  of  30-gauge  brass  or  aluminum  about  l/o  x 
%  inch,  and  bend  a  little  of  one  of  the  long  edges  of  each 
at  right  angles  to  the  rest  of  the  surface,  to  serve  as  handles. 
The  side  of  each  piece  opposite  to  the  handle  is  to  be  cov- 
ered with  soft  compound  from  the  heater  to  a  depth  of 
from  y$  to  14  inch. 

The  rectangles  are  called  "Bite  Lock  Trays." 


1.-.1 


Fig.  12G. 


Locking  the  Bites. 

Drop  the  pin  of  the  Incisor  Path  Marker  and  cause  the 
patient  to  close  the  jaw  so  that  the  point  of  the  marker 
will  be  in  the  point  of  the  incisor  path  tracing.  Instruct 
the  patient  to  hold  the  jaw  firmly  in  this  position.  Grasp 
the  handle  of  one  bite  lock  tray  with  the  pliers,  as  shown, 
apply  soft  compound  to  it.  Carry  it  into  the  mouth  so  that 
the  long  diameter  of  the  tray  is  parallel  to  the  occlusal 
plane,  and  take  an  impression  that  includes  the  notches 
in  the  buccal  surfaces  of  the  bite  rims.  Take  an  impres- 
sion of  the  other  side  in  the  same  manner.  When  the 
bite  lock  impressions  are  chilled  remove  and  place  them 
in  cold  water  until  the  impressions  are  poured  and  the 
casts  ready  for  mounting  on  the  articulator. 

This  method  is  equally  applicable  whether  compound 
impressions  and  bite  rims  are  used,  or  baseplate  compo- 
sition bases  and  wax  bite  rims. 


152 


Determining  the  Depth  of  Relief. 

The  depth  of  relict  of  any  individual  mouth  will  de- 
pend  upon  the  relation  of  the  hard  areas  in  the  center  of 
the  mouth  to  the  sofl  area  of  the  ridges,  on  the  form  and 
extent  of  the  bony  areas  in  the  center  of  the  mouth,  on 
the  necessity  of  preventing  interference  with  the  circula- 
tion in  the  palatine  vessels  and  on  the  history  of  previous 
dentures. 

The  depth  of  relief  is  estimated  on  the  amounl  of  settling 
anticipated  in  the  plate.  In  Class  I  and  Class  II  months. 
not  of  recent  extraction,  and  with  no  history  of  rapid 
settling,  only  shallow  relief  sufficient  to  offsel  the  warping 
in  vulcanizing  will  be  necessary.  When  the  ridges  exhibit 
much  soft  tissues,  and  the  mouth  is  flat,  only  slight  relief 
should  he  made.  In  recent  extraction  cases,  much  deeper 
relief  must  he  made  over  the  hard  areas. 

In  cases  where  there  is  a  marked  bony  prominence  in  the 
center  of  the  mouth  and  where  the  tissues  have  been  irri- 
tated by  the  pressure  of  previous  plates,  the  relief  must  be 
uniform  and  deep  over  the  hard  area. 

Any  interference  with  the  circulation  in  the  palatine 
blood  vessels  will  hasten  the  resorption  of  the  ridge  tissues 
and  will  cause  loss  of  fit  of  the  denture.  It  is  probable 
that  the  loss  of  fit  frequently  seen  in  dentures  constructed 
from  tight  fitting  impressions  is  due  to  this  cause.  Free- 
dom of  circulation  in  the  palatine  blood  vessels  may  be  as- 
sured by  scraping  the  impression  at  the  location  of  the 
palatine  foramina  as  described  for  Figure  126.  If  any 
bony  prominences  are  located  near  the  foramina,  the  relief 
should  provide  for  them. 

A  depth  of  relief  slightly  in  excess  of  immediate  needs 
will  do  no  harm. 

If  the  relief  is  made  in  the  impression  as  described  on 
the  following  page  it  will  result  in  a  denture  of  uniform 
thickness  over  the  palatal  surface.  Such  dentures  are  less 
likely  to  split  than  those  in  which  tin1  relief  is  made  on  the 
cast  after  opening  the  flask. 

153 


KJKL^ 


Fig.  127. 

Relieving  the  Impression. 

With  a  small  Kingsley  scraper,  relieve  an  area  about 
14  inch  in  diameter  to  a  depth  of  about  1/16  inch  over 
each  of  the  three  palatine  foramina  "B"  "B"  "B."  Draw 
a  median  line  "J"  through  the  area  "A"  and  lines  parallel 
to  it  "K-K"  on  each  side,  about  y$  inch  apart  until  the 
whole  area  is  lined.    Scratch  each  line  into  the  impression. 

With  a  large  hoe  excavator  channel  the  median  line 
to  the  depth  required  for  relief  as  far  as  the  line  "H." 
Diminish  the  depth  outside  the  line  "H"  so  that  at  the 
boundary  of  the  area  "A"  the  channel  passes  imperceptibly 
into  the  palatal  surface  of  the  impression.  Channel  the 
lines  "K-K"  not  quite  so  deep  as  the  median  line. 
Channel  successive  lines  to  a  shallower  depth.  Channeling 
establishes  the  depth  of  relief  required  in  different  parts 
of  the  area  "A."  Have  the  relieved  area  blend  imper- 
ceptibly into  the  palatal  surface  of  the  impression. 

With  a  scraper  cut  down  the  ridges  of  compound  be- 
tween the  channels  to  the  depth  of  the  channels.  Smooth 
the  scraped  area  with  sand  paper  and  finish  by  rubbing 
with  cotton  slightly  moistened  with  wood  alcohol. 

If  cutting  the  relief  has  reduced  the  "suction,"  examine 
the  impression  at  the  posterior  •  margin  and  the  frenum 
notch  and  add  black  wax  where  bubbles  are  seen  to  escape 
when  the  impression  is  seated. 

154 


Fig.  128. 

Preparing  the  Impressions  for  Making  Casts, 

Part  I. 

Any  tine  grooves  or  imperfections  in  the  ridge  surfaces 
of  the  impressions  may  be  filled  by  softening  Trubyte 
carding  wax  between  the  fingers  and  working  it  into  the 
depressions  with  a  lukewarm  wax  spatnla. 

Fold  a  sheet  of  soft  wax  and  with  the  doubled  sheet  form 
a  floor  to  fill  the  tongue  space  of  the  lower  impression  by 
attaching  it  to  the  lingual  side  of  the  lingual  flanges  about 
1/1 C)  inch  away  from  the  rounded  edge  of  the  flange  all 
around. 

Fold  a  sheet  of  the  sumo  wax  lengthwise  and  cut  a  strip 
1 /j  inch  wide,  the  long  way.  Attach  one  end  of  the  strip 
t<i  the  wax  floor  at  the  lingual  side  of  one  heel.  Bend  it 
around  the  heel,  around  the  buccal  and  lingual  surface  and 
around  the  other  heel  to  the  other  side  of  the  wax  floor. 
With  a  hot  spatula,  attach  it  to  the  impression,  keeping  it 
1/16  inch  away  from  the  rest  of  the  flange  and  taking  care 
nnt  to  soften  or  distort  the  flange. 

Attach  a  1  \  inch  strip  around  the  upper  impression  in 
the  same  way,  with  the  exception  that  across  the  posterior 
margin,  the  level  of  the  wax  should  he  1/16  inch  below  the 
level  of  the  palatal  surface  of  the  impression. 

155 


Fig.  129 

Preparing  the  Impressions  for  Making  Casts, 

Part  II. 

From  a  sheet  of  soft  wax,  folded  lengthwise,  cut  a  strip 
about  one  inch  wide  and  bend  around  each  model  outside 
the  narrow  wax  rim  first  placed.  Attach  this  strip  to  the 
top  of  narrow  wax  rim  with  a  hot  spatula.  When  the 
strip  has  encircled  the  model,  it  will  form  a  cup  which  will 
retain  the  cast  material.  The  edge  of  this  strip  should 
extend  far  enough  above  the  highest  point  of  the  impres- 
sion, when  in  position  for  pouring,  to  insure  a  model  at 
least  3/16  inch  thick  at  its  thinnest  part.  (A  sheet  of 
tin  or  lead  may  be  substituted  for  this  wax  strip.) 

When  the  casts  are  made  they  will  be  found  very  con- 
venient for  the  shaping  of  baseplates  and  flasking  and 
will  permit  accurate  reproduction  of  the  muscle  trimmed 
margins  in  the  dentures.  Coat  the  impression  and  wax 
addition  with  thin  Sandarac  Varnish. 


156 


Fig.  130. 

Protecting  the  Bite  Rims  and  Records  During 
Casting. 

Small  pieces  of  black  carding  wax  are  shown  above  at- 
tached to  the  occlusal  surface  of  the  upper  bite  rim  and 
the  occlusal  surface  of  the  Horseshoe  Plate.  This  wax 
protects  both  rims  and  especially  the  incisor  path  record 
during  the  jarring  of  the  cast  material.  Extend  the  pieces 
of  wax  along  the  Horseshoe  Plate  as  far  as  the  front  of  the 
incisor  path  record,  without  touching  it.  Lay  the  third 
piece  of  wax  across  the  others  above  the  record  but  not  in 
contact  with  it.  Do  not  place  wax  so  that  during  manipu- 
lation or  the  removal  of  the  wax  this  record  will  be  de- 
-t  roved. 

Additional  wax  may  be  added  to  make  the  impressions 
set  level. 


157 


Pig.  131. 


Mixing  the  Material  for  Casts. 

Weinstein's  Artificial  Stone  and  Spence's  Plaster  are 
preferable  to  plaster  of  Paris  for  casts.  The  manufac- 
turer's directions  for  the  use  of  each  are  given  on  .the 
packages.  We  employ  the  same  technic  to  free  both  from 
objectionable  bubbles.  To  avoid  confusion  only  the  technic 
for  Spence's  Plaster  is  given.  . 

Take  about  3y2  parts  of  Spence's  plaster  to  one  of 
water,  by  bulk.  Sift  the  plaster  slowly  into  the  water 
and  spatulate  thoroughly  against  the  sides  of  the  plaster- 
bowl  for  5  minutes,  using  a  bone  paper  cutter  as  a  spatula. 
When  mixing  is  finished  the  consistency  is  right  if  material 
dropped  from  the  end  of  spatula  will  not  flatten  out. 

Procure  an  enameled  tray  of  fibre  or  paper  mache,  like 
that  above  shown,  about  8  x  10  inches,  and  with  shallow 
sides.  Place  in  the  tray  about  3  ounces  of  the  mixed  Spence 
Plaster  and  jar  the  tray  sharply  against  the  top  of  the 
bench  until  bubbles  cease  to  appear  on  the  surface  of  the 
plaster.  If  bubbles  come  to  the  surface  but  do  not  break, 
break  them  by  tapping  with  the  finger. 

With  an  ordinary  flexible  plaster  spatula,  raise  some  of 
the  mixed  plaster  from  the  tray  and  place  in  the  incisor 
depression  of  either  impression. 

158 


Fig.  132. 

Making  the  Casts,  Part  I. 

Hold  the  impression  firmly  in  one  hand  and  jar  it 
sharply  against  the  bottom  of  the  other  hand.  Flow  the 
first  materia]  placed,  as  far  over  the  palatal  surface  as  it 
will  lid,  then  add  more  on  top  of  it  and  jar.  Repeat  until 
the  entire  surface  of  the  impression  is  covered  to  a  depth 
of  about  %  inch.  If  the  plaster  tends  to  collect  in  the 
ridge  depressions,  work  it  to  the  other  surface  with  the 
spatula  and  maintain  an  even  thickness. 

Add  to  the  Spence  Plaster  in  the  howl  enough  dry 
Spence  Plaster  to  bring  the  mix  just  to  that  consistency 
which  will  show  a  clean  fracture  when  broken  hetwecn  the 
fingers  hut  is  not  crumbly.  Mould  this  thickened  mass 
into  a  roll  about  half  an  inch  in  diameter  and  pack  into  the 
ridge  depressions  by  tapping'  with  the  fingers. 


159 


Fis.  133. 


Making  the  Casts,  Part  II. 

Continue  to  add  the  thickened  material  in  the  manner 
just  described,  tapping  each  portion  to  a  union  with  that 
already  in  the  impression,  until  the  cup  formed  by  the 
wax  rim  is  level  full,  as  shown  above.  In  handling  this 
material,  it  will  be  found  that  repeated  tapping  will  cause 
it  to  spread  better  than  it  can  be  made  to  do  by  greater 
pressure  applied  once  or  twice. 

The  object  of  mixing  this  material  to  two  consistencies 
is  to  eliminate  bubbles  and  yet  make  a  stronger  cast  than 
would  be  possible  if  the  thin  mixture  were  used  throughout. 

The  supporting  wax  may  be  removed  from  Spence 
Plaster  in  about  2  hours  and  the  impressions  removed  in 
about  4  hours.  The  wax  may  be  removed  from  Wein- 
stein's  Stone  models  in  about  6  hours  and  the  impressions 
removed  in  12  hours. 


160 


R  43°  38°  L 


Fig.  134. 

Reproducing  the  Descending  Inclination  of 
the  Condyle  Path,  Pakt  I. 

If  the  Gysi  Adaptable  articulator  is  to  lie  used,  it  should 
he  adjusted  to  reproduce  the  descending'  and  lateral  in- 
clinations of  the  condyle  path,  as  recorded  by  the  patient. 

Lav  the  card  with  the  record  of  the  descending'  inclina- 
tion of  the  condyle  path  on  the  bench  and  draw  a  line  long 
enough  to  reach  across  both  edges  of  the  card,  through  the 
Straight  center  portion  of  the  record  as  shown  under  "L" 
a  hove,  disregarding  any  short  curves  at  either  end.  The 
purpose  of  this  line  is  to  magnify  the  record.  It  is  much 
easier  to  accurately  measure  the  inclination  of  the  long  line 
than  that  of  the  shorter  actual  record.  A  transparent  rule 
such  as  that  beside  the  path  under  "R"  above  will  be  found 
advantageous  for  drawing  this  line. 

Place  the  point  of  the  aluminum  Degree  Plate  which 
forms  pari  of  the  articulator,  at  the  end  of  the  prolonged 

record  where  it  crosses  the  Lower  edge  of  the  card,  and  SO 
that    its  zero  side  coincides   with    the   lower  margin   of  the 

card.  Xote  where  the  line  continued  upward  through  the 
record,  crosses  the  upper  edge  of  the  Degree  Piute  and 
record  the  number  of  degrees  on  the  card  above  the  record. 

The  descending  inclination  of  the  righl  condyle  path  is 
here  43°  j   of  the  left   path   38°. 

161 


Fig.  135. 

Reproducing  the  Descending  Inclination  or 
the  Condyle  Path,  Part  II. 

The  descending  inclination  of  the  right  condyle  path  is 
to  be  reproduced  by  moving  the  pointer  "A"  on  the  right 
side  of  the  articulator,  on  the  vertical  Degree  Plate  "JB" 
until  it  registers  the  same  number  of  degrees  of  downward 
inclination  as  the  right  path  in  Figure  133,  43°.  The 
upper  line  on  this  Degree  Plate  registers  20°,  the  second 
line  30°  and  the  third  line  40°.  To  set  a  downward  in- 
clination of,  say  25°,  fix  the  pointer  half  way  between 
the  marks  for  20°  and  30°.  For  an  inclination  of  10°  set 
the  pointer  as  far  above  the  20°  line  as  the  30°  line  is 
below  it. 

To  move  the  pointer  "A"  loosen  the  setscrew  "C"  by 
means  of  the  pin  "D"  which  is  attached  to  the  straight 
Incisor  Guide  Pin.  Place  the  pointer  as  desired  and  before 
tightening  the  setscrew,  make  sure  that  the  vertical  flange 
of  the  artificial  fossa  is  in  contact  with  the  inner  side  of 
the  condyle  pin.  This  adjustment  may  be  effected  by  plac- 
ing a  knife  blade  between  the  pointer  "A"  and  the  Degree 
Plate  and  forcing  the  pointer  slightly  outward. 

Lock  the  setscrew,  taking  care  not  to  strip  the  threads. 
Adjust  the  inclination  on  the  left  side  in  the  same  way. 


162 


Pig.  13G 


Reproducing  the  Latebal  Inclination  or  the 
Condyle  Path.  Part  I. 

Lay  the  Condyle  Path  Register  on  a  piece  of  white  paper 
with  the  ground  sides  of  the  glasses  upward.  Place  the 
edge  of  a  transparent  ruler  along  the  record  and  starring 
al  the  point  "C"  in  "A"  where  the  record  crosses  the  base 
line,  draw  a  line  which  follows  the  general  inclination  of 
that  section  of  the  record  between  "C"  and  "LV  Prolong 
the  line  to  "E"  al  the  edge  of  the  glass. 

Place  a  card  so  thai  its  corner  is  at  "C"  and  its  lower 
margin  coincides  with  the  base  line,  and  draw  the  line 
"F"  perpendicular  to  the  base  line.  Prepare  the  record 
of  the  other  condyle  in  like  manner. 

Turn  the  Condyle  Path  Register  so  that  the  ground  side 
of  the  glasses  is  downward  as  in  "B."  Place  the  Degree 
Plate  which  comes  with  the  articulator  so  thai  its  point 
is  at  "C"  and  its  zero  side  coincides  with  the  line  "F." 
Read  the  number  of  degrees  recorded  by  the  line  "*('-K." 
.Vote  the  inclination  in  degrees  on  the  card  which  records 
the  downward  inclination.  Oo  the  same  with  the  record 
of  the  other  condyle.  The  right  lateral  inclination  is  13 
for  this  case  and  the  left  is  5°. 


Fig.  137. 


Reproducing  the  Lateral  Inclination  oe  the 
Condyle  Path,  Part  II. 

The  lateral  inclination  of  the  condyle  path  is  to  be  re- 
produced in  the  articulator  by  rotating  the  plate  "A"  which 
carries  on  its  nnder  side,  the  artificial  glenoid  fossa,  abont 
its  pivot  "B."  The  upper  surface  of  the  plate  "A"  is 
marked  to  show  the  lingual  inclination  of  the  vertical 
flange  of  the  fossa  on  its  other  side. 

The  farthest  backward  of  the  lines  is  marked  "0,"  and 
when  this  line  is  at  the  edge  of  the  slot  through  which  the 
plate  works,  the  condyle  cannot  move  laterally  but  must 
move-  straight  forward.  When  the  second  line  is  at  the 
edge  of  the  slot,  the  fossa  is  inclined  10°.  An  inclination 
of  15°  is  shown  by  the  short  line  half  way  between  the  10° 
and  20°  marks.  The  third  long  line  shows  an  inclination 
of  20°  and  the  fourth  such  line  an  inclination  of  30°. 

To  rotate  the  plate  "A,"  loosen  the  set  screw  which 
works  in  the  hole  "C"  and  which  has  here  been  removed  to 
allow  the  plate  and  its  markings  to  be  better  seen. 

When  the  proper  lateral  inclination  of  the  plate  "A"  is 
effected,  tighten  the  setscrew.  Adjust  the  plate  on  the 
other  side  of  the  articulator  in  the  same  way. 


164 


MHHI^^HH 


Pig.  138. 

Locking  the  Bite  Rims  for  Mounting. 

As  soon  as  the  wax  vims  about  the  cost  can  bo  removed, 
thoroughly  dry  the  Bite  Locks.  Remove  all  traces  of  wax 
from  the  occlusal  and  buccal  surfaces  of  the  bite  rim. 
Place  the  upper  and  lower  bite  rims  in  contact  and  sot  the 
Bite  Locks  into  the  notches  of  which  they  took  impressions. 
Drop  the  Incisor  Path  Marker  and  see  that  the  point  is  in 
the  point  of  the  record.  With  a  hot  spatula  seal  the  mar- 
gins of  the  Bite  Locks  to  the  buccal  surfaces  of  the  bite 
rims.  The  impressions  thus  locked,  are  ready  to  be  placed 
in  the  art  iculator. 

Raise  the  pin  of  the  Incisor  Path  Marker  and  luck  it  in 
this  position. 


165 


Fig.  139. 
166 


Mounting  Casts  on  the  Adaptable 
Articulator. 

Make  sure  that  all  the  set  screws  of  the  articulator  arc 
(Irmly  sel  to  prevenl  movemenl  of  the  parts. 

Substitute  the  Curved  Incisor  Guide  Pin  for  the  straight 
pin.  The  upper  end  of  this  pin  should  be  flush  with  the 
sleeve  which  holds  it.  Place  the  Gooseneck  in  the  black 
supporting  frame  and  hick  ii  by  means  of  the  setscrew. 
1  nserl  the  horizontal  end  of  the  ( looseneck  into  the  hole  in 
the  forward  end  of  the  center  block  of  the  Condyle  Path 
Register.  Push  the  rods  of  the  Horseshoe  Plate,  with  bites 
and  models  attached,  their  full  length  into  the  back  of  the 
same  block.     Do  not  change  the  positions  of  the  pencils. 

Rotate  the  milled  screws  of  the  Condyle  Path  Register 
so  as  to  bring  the  marks  made  in  Figure  123  to  the  ends 
of  the  milled  tracks. 

Carefully  introduce  the  articulating  frame  from  the  rear 
and  move  it  mil  il  the  curve  of  the  Incisor  Guide  Pin  partly 
encircles  the  front  of  the  Horseshoe  Plate  and  the  ends  of 
the  horizontal  pencils  are  directly  opposite  the  tops  of  the 
condyle  pins  when  viewed  from  front  and  top  and  equi- 
distant  from  them. 

If,  when  the  wings  of  the  Condyle  Path  Register  are  ad- 
justed so  that  the  marks  made  in  Figure  123  are  at  the 
ends  of  the  milled  tracks,  the  distance  between  the  points 
of  the  horizontal  pencils  is  so  ureal  as  to  make  difficull  the 
adjustment  of  the  pencils  to  the  condyle  pins  in  the  manner 
described  above,  the  wings  of  the  Register  may  be  moved 
in  the  following  manner.  When  the  points  of  the  horizon- 
tal pencils  are  nearly  equidistant  from  the  condyle  pins, 
measure  the  distance  between  the  pencil  and  the  condyle 
pin  which  appear  to  be  closer  together.  Beginning  at  the 
black  marks  shown  in  Figure  L23,  lay  oil'  this  distance  on 
each  wing  of  the  Register,  away  from  the  median  line, 
and  make  marks  similar  to  those  first  made.  Move  both 
wings  of  the  register  until  the  marks  just   made  are  at   the 

in; 


Mounting  the  Casts  on  the  Adaptable 
Articulator-  -Continued. 

ends  of  the  milled  i racks.  This  method  insures  moving 
each  pencil  an  equal  distance  toward  the  median  Line. 
Bringing  the  pencil  close  to  the  condyle  pins  in  this  man- 
ner makes  easy  the  establishment  of  correel  relations. 

Raise  or  lower  the  Gooseneck  until  the  points  of  the 
pencils  are  on  a  level  with  the  heads  of  the  condyle  pins. 

Some  patients  present  such  long  rami  that  it  is  impos- 
sible to  bring  the  points  of  the  horizontal  pencils  level  with 
the  heads  of  the  condyle  pins  because  the  lower  cast,  even 
if  very  thin,  strikes  the  lower  how  of  the  articulator.  In 
such  cases  adjust  the  Gooseneck  until  the  lower  cast  jusl 
clears  the  lower  how.  Move  the  Condyle  Path  Register 
until  the  pencils  on  the  two  sides  are  equal  distances  above 
the  condyle  pins  when  viewed  from  the  front,  and  in  the 
same  relation  to  them  as  the  normal  case  viewed  from 
the  side  and  from  above. 

The  casts  are  now  in  position  to  be  sealed  to  the  articu- 
lator. 

If  the  casrs  arc  made  of  Spence  plaster,  it  will  he  unnec- 
essary to  scire  or  wet  them  for  the  attachment  of  plaster  of 
Paris.  With  Silex,  paint  an  area  about  an  inch  in  diameter 
in  the  center  of  the  upper  surface  of  the  upper  cast.  This 
reduces  the  area  of  attachment  of  the  plaster  and  makes 
it  easier  to  free  the  cast  for  flasking. 

Make  a  medium  thick  mix  of  plaster  of  Paris  and  How 
over  the  upper  how  and  cast,  so  that  it  will  he  at  leasl  '  [ 
inch  thick  where  if  covers  the  how. 

When  the  plaster  attaching  the  upper  cast  to  the  upper 
how  is  hard,  carefully  remove  the  Condyle  Path  Register 
from  the  Horseshoe  Plate.  Invert  the  articulator  as  in 
Figure  1  U  and  raise  the  lower  how  out  of  contact  with 
the  Incisor  Guide  Pin.  Paint  an  area  an  inch  in  diame- 
ter in  the  center  of  the  cast  with  Silex  and  heap  plaster, 
mixed  medium  thick,   on   the  bottom  of  the  lower  cast. 

1G9 


Fig.  141. 


Mounting  the  Casts  on  the  Adaptable 
Articulator — Continued. 


Bring  the  lower  bow  downward  into  contact  with  the 
Incisor  Guide  Pin. 

.  Make  sure  that  the  rotation  pins  are  in  contact  with  the 
vertical  wall  of  the  groove  in  which  they  work  and  that 
the  condyles  are  in  contact  with  the  glenoid  fossae.  If  the 
rotation  points  and  condyle  pins  are  not  in  the  relation 
described,  hold  what  is  normally  the  upper  part  of  the 
articulator,  and  pull  downward  and  backward  on  what  is 
normally  the  lower  part,  while  the  plaster  is  soft,  until  the 
pins  are  in  the  proper  positions. 

Form  plaster  over  the  lower  bow  so  as  to  completely  en- 
close it  and  attach  it  firmly  to  the  cast.  Press  a  sheet  of 
glass  upon  the  soft  plaster  until  it  touches  the  articulating 
frame  in  front  and  back,  to  form  a  flat  surface  on  which 
the  articulator  may  rest. 


170 


'ig.  1  12. 


Locating  the  Rotation  Points,  Part  I. 

Remove  the  Bite  Locks  from  both  sides.  Loosen  the  set- 
screw  holding  the  rotation  pin  on  the  right  side,  and  move 
the  pin  as  far  from  the  center  as  possible.  Remove  the  In- 
cisor Guide  Pin.  Hold  the  casts  as  shown  and  by  straight- 
ening the  fingers  raise  the  upper  bite  rim  slightly  out  of 
contact  with  the  Horseshoe  Plate.  This  prevents  the  [n- 
cisor  Path  Marker  destroying  the  pattern  on  the  Horse- 
shoe Plate.  Move  the  upper  cast  to  the  left  unl  il  the  poinl 
of  the  Incisor  Path  .Marker  is  near  the  left  and  usually  in 
front  of  the  incisor  path  record.  Make  sure  that  the  left 
condyle  pin  is  in  contact  with  its  fossa. 

By  pressure  outward  on  the  lock  nut,  move  the  rotation 
pin  away  from  the  median  line.  Watch  the  poinl  of  the 
Incisor  Path  Marker,  and  when  il  is  seen  to  enter  the  in- 
cisor path  record,  tighten  the  lock  nni  jusl  enough  to  fix 
the  rotal  ion  pin. 

Bear  in  mind  thai  the  righl  rotation  poinl  governs  the 
movement  of  the  [ncisor  Path  Marker  on  the  lefl  side  of 
the  median  line  and  vice  versa. 


171 


Locating  the  Rotation  Points,  Part  II. 

Allow  the  upper  cast  to  move  back  toward  the  median 
line  and  note  whether  the  point  of  the  Incisor  Path  Marker 
follows  the  anterior  margin  of  the  incisor  path  record.  If 
it  does,  tighten  the  lock  nut  just  a  little  by  means  of  the 
L  shaped  pin,  but  take  care  not  to  strip  the  threads. 

If  the  point  of  the  Marker  travels  in  front  of  the  margin 
of  the  record,  move  the  rotation  point  away  from  the 
median  line.  If  it  diverges  inward  from  the  margin  of  the 
record,  move  the  rotation  point  toward  the  median  line. 

Adjust  the  rotation  point  on  the  other  side  in  the  same 
manner. 


172 


Fig.  144. 

Marking  Lines  on  the  Upper  Cast. 

Remove  the  Incisor  Path  Marker.  With  n  knife,  pro- 
long the  median  line  and  the  cuspid  location  lines  upward 
on  the  cast.  With  a  pair  of  dividers,  prick  off  points  on 
the  upper  cast  in  a  line  parallel  to  the  occlusal  plane  and 
make  a  permanent  line,  "A-B"  through  them.  With  the 
dividers  space  off  the  distance  "C-E"  on  the  line  "('-IT' 
equal  to  the  distance  from  the  point  "C"  to  the  plane  of 
occlusion.  If  the  plane  of  occlusion  is  lost  during  the 
arrangement  of  the  teeth,  it  may  he  re-established  parallel 
to  the  line  "A-B"  and  as  far  below  it  as  from  "C"  to  "E." 
This  line  "A-B"  is  especially  valuable  while  one  is  learn- 
ing to  arrange  teeth  but  may  not  he  so  important  when  one 
is  proficient.  Tt  was  therefore  omitted  from  the  casts  in 
the  illustrations  that  follow. 

Insert  a  knife  under  the  Horseshoe  Plate  and  pry  it 
from  the  bite  rim.  Invert  the  art  iculator  and  hold  the  bite 
rims  together.  Place  a  knifeblade  againsl  tin-  buccal  sur- 
face of  tlie  lower  at  the  right  cuspid  and  inscribe  the  lo- 
cation of  the  anterior  margin  of  the  lower  bite  rim  on  the 
occlusal  surface  of  the  upper,  from  cuspid  to  cuspid.  This 
will  permit  a  correct   re-formal  ion  of  the  lower  bite  rim. 


173 


1  i 

il 

-'■-"■  ^" 

Fig.  145. 

Removing  the  Lower  Impression  erom  the 
Cast. 

Separate  the  lower  section  of  the  articulator  from  the 
upper  by  the  method  described  in  Fig.  156.  Immerse  the 
lower  impression  in  water  of  120°  F.  by  suspending  the 
lower  part  of  the  articulator  over  the  edge  of  the  hot  water 
vessel  in  the  manner  shown,  and  adding  water  until  it  cov- 
ers the  compound  but  does  not  reach  the  plaster.  When 
the  compound  is  sufficiently  soft,  remove  it  from  the  im- 
pression. Do  not  remove  the  upper  impression  from  the 
upper  cast  at  this  time. 

Powdered  soapstone  or  talcum  rubbed  on  the  impres- 
sion surface  of  the  cast  will  give  it  a  fine  finish  and  facili- 
tate the  adaptation  of  the  baseplate. 


174 


Adapting  Baseplate. 

The  following  fcechnic  is  for  adapting  the  upper  base- 
plate.     Adapt  the  lower  in  like  manner. 

Adjust  the  gas  so  that  it  produces  a  Bunsen  flame  4 
inches  high.  Hold  ;i  blank  of  Dentsply  Baseplate  Com- 
pound as  shown  and  pass  the  outer  2/3  sideways  in  con- 
tact with  the  top  of  the  flame,  so  that  the  blank  crosses 
the  flame  in  one  second.  Pass  it  5  times  in  this  way. 
If  the  blank  be  then  held  horizontally  the  healed  portion 
should  maintain  its  shape  for  about  a  second  and  then 
wilt.  Ef  the  baseplate  be  held  in  the  flame  until  it  wilts, 
it  will  he  overheated  and  will  burn  the  Angers  during 
adaptat  ion. 

Place  the  blank  on  the  upper  cast  as  shown  in  Figure 
117  and  adapt  the  palatal  portion  of  the  softened  area 
closely  to  the  cast  by  pressing  for  aboul  hall'  a  second  in 
one  place,  then  raising  the  finger  and  moving  it  forward 
and  repeating  the  pressure.  The  heat  may  he  uncomfort- 
able to  the  finger  if  the  pressure  is  continuous.  Continue 
the  adaptation  over  the  alveolar  border  and  the  buccal 
ami  labial  surfaces. 

When  the  adapted  section  is  thoroughly  chilled,  use  it 
as    a    handle    while    heating    the    other    side    which    is    then 

adapted.     Any  small  portion  of  the  flange  not  satisfactorily 
adapted  may  he  separately  heated  and  adapted. 

175 


Fig.  148. 


Fig.  149. 


Adapting  Baseplate — Continued. 

Figure  148  shows  a  view  of  the  palatal  side  of  the 
partly  adapted  baseplate  from  the  rear.  Several  creases 
are  seen  at  the  median  line,  in  front,  where  the  baseplate 
was  folded  when  it  was  adapted  to  the  labial  surface.  Turn 
the  baseplate  so  that  the  left  margin  points  directly  down- 
ward and  hold  the  folded  portion  against  the  side  of  the 
base  of  the  flame  for  one  second.  Remove  and  wait  two 
seconds  to  allow  the  heat  to  penetrate  the  material;  then 
hold  against  the  flame  for  a  second.  Repeat  this  form  of 
heating  until  the  surface  of  the  baseplate  in  front  of  the 
ridge  is  very  soft ;  then  wait  two  or  three  seconds.  Place 
the  baseplate  upon  the  cast  and  with  intermittent  finger 
pressure  adapt  the  baseplate  to  the  ridge  so  that  the  creases 
are  eliminated  as  shown  in  the  median  line  in  Figure  1 50. 

The  line  "C-C-C"  marks  the  outer  margin  of  the  exten- 
sion on  the  cast  made  by  the  narrow  wax  rim  added  in 
Figure  133.  :  Trim  away  the  surplus  which  extends  out- 
ward from  this  line.  It  can  be  best  trimmed  by  passing 
the  surface  once  through  the  flame  and  cutting  with 
shears. 

Heat  the  baseplate,  which  rests  on  tlie  extension  of  the 
cast  material,  by  passing'  it  once  through  the  flame  and 
folding  the  heated  portion  upon  the  buccal  and  labial  sur- 
faces by  pressure  as  shown  in  Figure  150  and  to  the  fin- 
ished form  shown  on  the  right  side  of  Figure  151.     The 


176 


Fig.  150. 


Fig.  151. 


Adapting  Baseplate — Continued. 

folded  portion  is  not  heated  enough  to  fuse  with  the  base- 
plate againsl  which  it  is  folded.  Fold  the  extension  across 
the  heel  in  the  same  manner.  The  margins  thus  shaped 
must  conform  to  the  muscle  trimmed  margins  of  the  im- 
pression and  constitute  a  valuable  reinforcement  of  the 
baseplate. 

When  the  cast  presents  an  undercut  which  makes  it  dif- 
ficult to  withdraw  the  baseplate  without  marring  the  im- 
pression, adapt  the  baseplate  only  so  far  beyond  the  be- 
ginning of  the  undercut  as  will  permit  withdrawal  without 
binding. 

[f  the  baseplate  is  broken  during  manipulation,  place 
the  broken  pieces  on  the  cast  with  the  edges  together.  With 
a  very  hot  spatula  fuse  the  edges.  Melt  some  of  the  sur- 
plus baseplate  in  the  flame  as  sealing  wax  is  melted  and 
drop  it  on  the  break.  Smooth  the  surface  with  the  hot 
spat  nia. 

In  making  partial  dentures,  especially  lowers,  any 
baseplate  extending  about  the  teeth  should  be  reinforced  by 
embedding  hot  wires  in  the  baseplate,  melting  baseplate 
over  the  wires  and  smoothing  the  surface  with  a  hot 
spatula. 

'Idie  lower  baseplate  should  be  formed  so  thai  the  lingual 
and  bucco-labial  margins  are  turned  up  in  ihe  manner 
described  for  the  margins  of  the  upper, 


177 


Fig.  152. 

Re-forming  the  Lower  Bite  Rim. 

The  lower  baseplate  is  in  position  on  the  lower  cast. 
Soften  the  compound  which  formed  the  lower  impression 
and  bite  rim  in  hot  water  and  mould  it  into  a  roll  half  an 
inch  in  diameter  and  about  as  long  as  the  bite  rim.  Place 
this  on  the  lower  baseplate  so  that  the  center  of  the  mass  is 
approximately  over  the  center  of  the  lower  ridge.  With 
the  incisor  guide  pin  in  place,  close  the  upper  bite  rim 
upon  the  roll. 

When  the  roll  is  cool,  trim  the  excess  fullness  from  the 
labial  surface  until  the  line  scratched  upon  the  occlusal 
surface  of  the  upper  bite  rim  in  Figure  152  shows  when 
the  upper  and  lower  are  in  contact.  Trim  the  buccal  sur- 
faces from  the  cuspids  to  the  heel  flush  with  the  buccal 
surfaces  of  the  upper  rim. 

With  a  flame  from  the  mouth  blow  pipe  and  the  alcohol 
lamp,  heat  the  occlusal  surface  of  the  lower  bite  rim  to  a 
very  shallow  depth  and  press  it  upon  a  moist  glass  to  smooth 
the  surface,  but  do  not  change  the  height  of  the  plane  of 
occlusion.  Attach  the  bite  rim  to  the  lower  baseplate  as 
follows.  With  a  very  hot  flame  from  the  mouth  blow  pipe 
and  an  alcohol  lamp,  heat  the  compound  in  the  deepest 
part  of  the  impression  made  by  the  ridge  of  baseplate,  until 
it  sputters,  but  do  not  heat  the  sides  or  margin  of  this  de- 
pression. Place  the  bite  rim  upon  the  lower  baseplate  and 
close  the  upper  upon  it. 

178 


u 


FiS.  150. 

Trimming  and  Marking  the  Lower  Bite  Rim. 

With  a  sharp  knife  trim  the  lingual  surface  of  the  lower 
bite  rim  to  the  form  shown  here.  This  surface  slopes  from 
the  lingual  margin  of  the  baseplate  upward  and  a  little 
outward.  This  places  the  compound  in  the  relation  to  the 
ridge  which  it  is  desired  that  the  finished  denture  shall 
occupy.  This  form  of  lingual  surface  must  sometimes  he 
modified  in  the  region  of  the  lower  second  molars,  bul  when 
it  can  be  effected  ii  allows  free  action  of  the  tongue  withoul 
danger  of  displacing  the  lower  denl  ure. 

Trim  the  buccal  surface  so  thai  the  width  of  the  occlusal 
surface  ol  the  rim  in  the  bicuspid  region  is  aboul  equal  to 
the  bucco-lingual  diameter  of  the  bicuspids  and  the  width 
of  the  surface  in  the  molar  region  is  about  equal  to  the 
buCCO-lingual  diameter  of  the  molars.  Locate  the  center 
of  the  occlusal  surf  ace  al  the  cuspids  and  al  the  heels.  Con- 
ned   the    two    points    with    lilies    having    a    slight    outward 

curvature  similar  to  thai  of  the  rim.  as  shown  above. 

179 


Fig.  154. 

Building  the  Lower  Bite  Rim  Forward. 

Soften  a  small  quantity  of  Dentsply  Baseplate  Wax  over 
the  flame  and  with  it  build  the  labial  surface  of  the  lower 
bite  rim  forward  to  be  flush  with  the  labial  surface  of  the 
upper  bite  rim.  The  upper  bite  rim  is  to  be  rebuilt  in 
wax,  and  this  method  of  adding  to  the  lower  affords  a  guide 
to  assist  in  establishing  proper  fullness  in  the  upper  bite 
rim. 

Remove  the  upper  impression  from  the  cast,  using  the 
same  technic  as  was  described  for  the  lower  in  Figure  150. 

Make  the  upper  base  plate,  using  the  technic  described 
for  Figures  146  to  151  inclusive. 


180 


Fig,  155. 

Re-forming  the  Upper  Bite  Rim. 

TIi is  lute  rim  is  to  l>o  re-formed  in  wax.  Pass  the  lone; 
diameter  of  a  sheet  of  Dentsply  base  plate  wax  above  a 
bunsen  flame  until  one  side  of  it  is  fluid.  Hold  it  with  the 
lluid  side  upward.  Double  the  melted  side  upou  itself.  Be- 
ginning at  one  end  of  the  fold,  pinch  the  softened  surfaces 
together,  gradually  working  toward  the  other  end.  Repeat 
this  heating,  folding  and  pinching  process  three  times  in 
all.  Xow  heat  the  strip  and  double  it  lengthways  upon 
itself.  When  the  folding  is  complete,  grasp  two  surfaces 
of  the  strip  so  formed  between  the  thumb  and  index  fingei 
of  one  hand,  and  the  two  remaining  surfaces  between  the 
thumb  and  index  finger  of  the  other  hand  and  gradually 
work  the  roll  between  the  fingers,  pinching  it  into  the  form 
of  a  square  bar. 

Place  the  incisor  imide  pin  in  position.  Pay  this  square 
bar  of  wax  on  the  occlusal  surface  of  the  lower  bite  rim 
and  close  the  upper  upon  it.  Trim  the  buccal  margins 
flush  with  the  buccal  margins  of  the  lower  bite  rim.  trim 
the  Labial  margin  flush  with  the  labial  margin  of  the  wax 
addition  to  the  lower.  Shape  the  upper  part  of  the  labial 
surface  t « >  about  the  fullness  and  the  form  of  the  compound 
bite  rim  which  was  removed.  The  illustration  above  shows 
the  completed  upper  wax  with  the  wax  addii  ion  to  the  front 
el'  the  lower  bite  l'iin  removed. 


1S1 


Fig.  15G. 


Removing  and  Replacing  the  Upper  Part  of 
the  Adaptable  and  Simplex  Articulators. 

Grasp  the  front  portion  of  the  articulator  between  the 
thumb  and  first  finger  of  the  right  hand  as  shown.  Grasp 
the  rear  vertical  portion  of  the  articulating  frame  with 
the  first  three  fingers  of  the  left  hand  and  place  the  end 
of  the  left  thumb  under  the  front  end  of  the  vertical 
flange  of  the  fossa.  Push  directly  upward  on  this  flange 
until  the  rotation  pin  rises  above  the  level  of  the  front 
wall  of  the  groove  in  which  it  works.  Carry  the  end  of 
the  left  thumb  forward  and  the  upper  part  of  the  frame 
with  it  until  that  part  of  the  articulator — in  contact,  with 
the  spring — slides  out  from  under  the  spring  and  the 
upper  section  of  the  articulator  is  separated  from  the 
lower. 

To  assemble  the  articulator  reverse  the  procedure  de- 
scribed above.  Locate  the  left  condyle  and  the  left  rota- 
tion pin  correctly  and  engage  the  web  of  the  articulator 
under  the  spring,  place  the  left  thumb  under' the  for- 
ward end  of  the  right  fossa.  Now  grasp  the  front  part 
of  the  articulator  as  illustrated  so  that  the  Guide  Pin 
is  in  contact  with  the  Incisor  Guide  Incline,  then  press 
upward  and  backward  with  the  thumb  until  the  rotation 
pin  clears  the  anterior  wall  of  its  groove.  Release  the 
upward  pressure,  when  the  rotation  pin  and  the  condyle 
will  settle  into  their  proper  locations. 

182 


Part  IV 
Arranging  The  Teeth 


Arranging  the  Teeth. 

The  upper  bite  rim  was  formed  to  give  a  desired  ex- 
pression to  the  upper  lip  and  in  arranging  teeth  it  is 
essential  that  they  maintain  the  fullness  and  curvature 
established  by  this  rim.  Begin  at  the  central  on  each  side 
and  work  backward  to  the  cuspid.  Detailed  instructions 
for  setting  these  teeth  will  bo  given. 

The  upper  bicuspids  and  molars  are  to  be  so  placed 
that  the  center  of  their  longitudinal  grooves  will  be 
as  nearly  over  the  lines  traced  on  the  occlusal  surface  of 
the  lower  bite  rim  in  Figure  141)  as  the  curvature  of  the 
upper  bite  rim  and  esthetics  will  permit. 

It  is  usually  better  to  allow  the  upper  teeth  to  set 
outside  of  the  upper  ridge  a  little  rather  than  move  the 
lower  teeth  into  the  tongue  space. 

When  the  upper  teeth  are  all  in  position,  the  lower 
teeth  on  each  side  will  be  set  in  the  following  order, 
first  molar,  second  bicuspid,  first  bicuspid;,  cuspid,  in- 
cisors, and  second  molars. 

In  setting  the  teeth  use  only  enough  wax  about  each 
tooth  to  attach  it  to  the  baseplate,  leaving  the  addition 
of  wax  for  the  restoring  of  expression  until  the  teeth  have 
been  tried  in  the  mouth  and  satisfactorily  adjusted.  It 
is  advantageous  to  use  as  little  wax  as  possible  in  placing 
the  teeth  because  the  shrinkage  of  a  large  quantity  of 
fluid  wax  may  distort  the  baseplate  and  pull  the  teeth 
out  of  the   desired  position. 

To  begin  setting  the  teeth,  cut  a  place  clear  through 
the  upper  bite  rim,  on  one  side  of  the  median  line,  as 
shown,  large  enough  to  receive  the  upper  central  incisor. 


184 


Arranging  The  CJppeb  Anteriors. 

Remove  the  upper  bow  from  the  articulator.  Procure 
;i  Trubyte  Occlusal  Plane  or  a  flat  piece  oi  wood  or  alumi- 
iiiim  2  j  2  inches  square,  and  use  it  as  shown  in  the  follow- 
ing illustrations  to  take  the  place  of  the  occlusal  surface 
of  the  lower  bite  rim. 

Before  waxing  the  upper  central  in  place,  try  lor  me- 
chanical suitability.  II  uecessary  carve  away  the  base- 
plate under  the  tooth  or  grind  the  ridgelap,  or  do  hoih 
so  that  the  tooth  will  uol  rest  directly  against  the  cast. 
The  long  ;i\is  of  the  upper  central  should  be  vertical  when 
seen  from  the  front  and  inclined  downward  and  forward 

when  seen    from   the  side  ;is  shown    in   "  I '."   and   "C".        The 

incisal  edge  is  in  contact  with  the  occlusal  plane.  The 
upper  centrals  are  not  sel  ;it  right  angles  to  the  median 
lino,  luii  the  distal  angles  are  inclined  slightly  backward 
and  begin  the  curvature  of  the  tooth  row  to  follow  the 
contour  of  the  bite  rim. 


is;, 


Fig.  158. 

Arranging  the  Upper  Antebiors — Continued 

Cut  a  space  through  the  upper  bite  rim  for  the  upper 
lateral  and  try  it  in  place  as  the  central  was  tried.  Set 
it  so  that  the  incisal  edge  is  about  %  of  a  millimeter  above 
the  level  of  the  occlusal  plane  and  so  that  the  long  axis 
is  inclined  as  shown  in  "B"  and  "0."  This  downward 
and  forward  inclination  of  the  vertical  axis  of  the  upper 
laterals  results  in  making  the  neck  of  this  tooth  less  promi- 
nent than  that  of  the  upper  central.  This  depression  will 
be  found  very  valuable  when  giving  expression  to  the 
teeth. 

The  incisal  edges  of  the  laterals  are  set  to  maintain  the 
curvature  established  by  the  incisal  edge  of  the  upper 
bite  rim,  as  shown  at  "B." 


186 


Kiu.  i.v.i. 

Arranging  the  Upper  Anteriors — Continued 

('lit  a  space  clear  through  the  upper  bite  rim  to  re- 
ceive the  upper  cuspid.  Try  the  tooth  for  length  as  the 
central  and  lateral  were  tried.  Sel  the  tooth  so  thai  its 
tip  just  touches  the  occlusal  plane  and  its  long  axis  is 
inclined  as  shown  in  "I!"  "C"  and  at  the  edge  of  the 
toot  1 1  coin  i urn'  the  curve  of  the  l>iie  rim  as  shown  at  "  1  >". 

The  labial  ridge  o1  the  cuspid  is  properly  the  dividing 
line  between  the  labial  and  buccal  sections  of  the  ridge. 
I  he  labial  surface  mesial  to  the  ridge  faces  the  lip  and 
maintains  the  general  curvature  established  bv  the  cen- 
tral and  lateral.  The  surface  distal  to  this  ridge  laces 
the  cheek  and  begins  the  curvature  characteristic  of  the 
bicuspids  and  molars.  The  effecl  of  setting  Trubvte  cus- 
pids in  this  position  is  to  carry  the  distal  angles  farther 


1ST 


Fig.  1G0. 


Arranging  the  Upper  Anteriors — Continued. 

inward  toward  the  median  line  than  has  been  possible 
with  the  conventional  forms  of  cuspids.  When  Trubyte 
cnspids  are  set  in  this  way,  only  the  mesial  aspect  can  be 
seen  from  the  front.  This  permits  the  use  of  teeth  large 
enough  for  the  month,  without  their  appearing  too  large. 
The  esthetic  effect  of  this  arrangement  is  greatly  enhanced 
by  the  natural  shading  of  the  teeth  in  the  set- 
When  the  central,  lateral  and  cnspid  of  one  side  have 
been  set,  set  the  central,  lateral  and  cnspid  on  the  other 
side  in  the  same  manner. 

Replace  the  upper  part  of  the  articulator  in  the  manner 
described  for  Figure  156  and  use  the  occlusal  surface  of 
the  lower  bite  rim  as  the  occlusal  plane  while  setting  the 
upper  bicuspids  and  molars. 


188 


Fig.  161. 

Arranging  the  Upper  Posteriors. 

When  the  bite  is  so  close  as  to  make  it  impossible  to 
use  the  length  of  bicuspids  and  molars  desired  without 
destructive  grinding,  the  base  plate  against  which  the 
teeth  are  to  rest  should  be  scraped  as  thin  as  possible 
without  perforating  it.  Trubyte  bicuspids  and  molars 
are  made  in  four  mcsio-distal  widths  28,  30,  32,  and  o4 
millimeters.  Each  width  is  made  in  three  vertical  Lengths 
known  as  short,  medium  and  long,  distinguished  by  the 
letters  "S,"  "M,"  "L"  on  the  neck  end.  The  manufac- 
turer's card  with  the  anteriors,  the  bicuspids  and  molars 
of  the  mcsio-distal  width  and  vertical  length  most  suit- 
able for  the'  average  case.  The  range  of  length  makes  ir 
possible  for  the  dentist  to  select  shorter  or  longer  teeth 
to  accompany  any  given  anteriors,  if  his  judgmenl  so 
indicates.  Tie  may  also  select  wider  or  narrower  bicuspids 
and  molars  than  those  regularly  carded,  but  when  bicuspids 
and  molars  wider  than  those  regularly  carded  are  se- 
lected to  go  with  any  given  anteriors.  the  mesial  sides  of 
the   lower    lirst    bicuspids   and    perhaps    the   distal    sides   of 

the  lower  cuspid  will  require  some  grinding,  to  provide 

room  for  the  placing  of  the  lower  anterior. 


1S9 


Arranging  the  Upper  Posteriors,  Continued. 

Fit  each  posterior  tooth  to  its  position  before  waxing 
it  in  place,  as  the  anteriors  were  fitted.  Make  sure  that 
each  tooth  is  short  enough  so  that  there  is  a  free  space  of 
at  least  a  millimeter  between  it  and  the  baseplate.  Cut 
a  strip  one-half  inch  wide  along  the  side  of  a  sheet  of 
Dentsply  Baseplate  Wax  and  soften  one  end  of  it  in  the 
flame.  Detach  a  small  portion  and  form  it  into  a  cone. 
Soften  the  end  of  the  cone  in  the  flame  and  force  it  about 
the  pins  or  into  the  recess  in  the  diatoric  tooth.  Using  the 
tooth  as  a  handle,  soften  the  other  end  of  the  cone  and 
press  it  upon  the  ridge  with  the  tooth  in  approximately  the 
correct  position.  Close  the  articulator  so  that  the  incisor 
guide  pin  comes  into  contact  with  the  incisor  guide  in- 
cline. Adjust  the  teeth  so  that  the  center  of  the  longitu- 
dinal groove  is  over  the  front-to-back  line  on  the  occlusal 
surface  of  the  lower  bite  rim.     The  buccal  cusp  of  the 


190 


Fi«.  163 


Arranging  the  Uppee  Posteriors,  Continued. 


upper  first  bicuspid  should  touch  the  occlusal  surface  of 
the  lower  bite;  the  lingual  cusp  should  be  raised  about  one- 
half  millimeter  above  that  rim.  When  the  tooth  is  first 
placed,  the  long  axis  of  the  tooth,  as  seen  from  the  buccal, 
should  be  vertical,  as  shown  at  "A"  in  Figure  163.  This 
may  be  slightly  modified  in  establishing  articulation. 

The  second  bicuspid  should  be  set  like  the  first  except 
that  both  cusps  touch  the  opposing  bite  rim,  as  shown  at 
"B"  in  Figure  163.  Rotate  both  bicuspids  upon  their 
long  axes  so  that  the  occlusal  surfaces  are  inclined  as  shown 
by  the  lines  in  "C,"   Figure  L63. 

With  the  straight  edge  of  the  Trubyte  Occlusal  Plane 
test  the  position  of  the  buccal  surface  of  the  bicuspids  in 
relation  to  the  cuspids.  When  these  teeth  are  in  proper 
relation  for  the  average  case,  the  straight  edge  should 
touch  the  buccal  surfaces  of  all  three  teeth. 

101 


Fig.  164 

Arranging  the  Upper  Posteriors,  Continued. 

Attach  the  upper  first  molar  to  the  ridge  as  the  bicuspids 
were  attached.  The  long  axis  of  this  tooth,  when  seen 
from  the  buccal  is  inclined  downward  and  backward  as 
shown  at  "A"  Figure  164.  Only  the  mesio-buccal  cusp 
of  this  tooth  should  touch  the  occlusal  surface  of  the 
opposing  bite,  the  disto-lingual  cusp  being  slightly  raised 
and  the  buccal  cusp  being  raised  about  three-quarters  of  a 
millimeter  out  of  contact,  as  shown  in  "B,"  Figure  164. 
This  arrangement  produces  the  average  compensating 
curve.  When  a  greater  curvature  is  required,  the  distal 
cusps  should  be  elevated  more.  The  tooth  should  be  ro- 
tated upon  its  long  axis  as  shown  at  "C"  in  Figure  164. 

The  upper  second  molar  is  now  placed  in  position,  with 
its  lingual  cusp  lightly  touching  the  occlusal  plane  and 
the  buccal  cusp  raised  about  one  and  one-half  millimeters 
out  of  contact.  If  a  greater  curvature  is  desired,  the 
lingual  cusp  should  be  elevated  out  of  contact  and  the 
buccal  cusp  elevated  in  a  corresponding  degree.  The  long 
axis  seen  from  the  buccal,  is  inclined  downward  and  back- 
ward more  than  was  the  first  molar. 

192 


ft 


WORKING  YjJ     BALANCING 

BITE  ^/VK'       BITE 


v\a.  [<;.-, 


LINES  SHOWING  TOOTH    MOVEMENT 


IN 
WORKING 
CONTACT 


9    V, 

.48  Q 


IN 

BALANCING 

CONTACT 


Fig.  1G6 


WW 

Kr  ">      A. 

J        ¥ 

^'D-l:2 

0 

\ 

WORKING  BITE 

LEFT 

SIDE 

Fig.  1G7 


TrtffS 


1 


BALANCING   BITE     LEFT  SIDE 
Fig.  168 

Description  on  page  following. 

193 


Working  and  Balancing  Molar  Contacts. 

The  dotted  triangle  in  Figure  165  shows  the  rest  posi- 
tion of  the  mandible.  The  triangle  in  solid  outline  and 
the  diagrams  of  the  teeth  show  the  position  of  the 
mandible  during  mastication  on  the  patient's  right  side. 
The  side  on  which  the  patient  is  masticating  is  commonly 
referred  to  as  the  "working  side."  The  opposite  side  is 
the  "balancing  side."  When  the  upper  and  lower  teeth 
come  into  working  contact,  the  upper  and  lower  buccal 
margins  are  interdigitated.  The  movement  of  the  teeth 
on  the  working  back  to  a  position  of  rest  is  nearly  at  right 
angles  to  the  median  line.  The  movement  of  the  teeth  on 
the  balancing  side  is  much  more  nearly  parallel  to  the 
median  line.  The  arrows  on  this  diagram  are  those  of 
the  movement  of  the  teeth  on  the  articulator. 

The  white  lines  on  the  occlusal  surface  of  the  molars  "In 
Working  Contact/'  in  Figure  166,  show  the  line  of  move- 
ment of  the  lower  teeth  across  the  uppers  during  mastica- 
tion. The  white  lines  across  the  occlusal  surfaces  of  the 
molars  bracketted  in  Figure  166  with  the  title  "In  Bal- 
ancing Contact"  show  the  line  of  movement  of  the  lower 
molars  across  the  uppers  on  the  balancing  side.  The 
arrangement  of  teeth  to  harmonize  with  these  lines  of 
movement  will  be  easy  if  they  were  carved  with  these  move- 
ments in  view;  otherwise  it  will  be  difficult.  Trubyte 
teeth  were  carved  to  produce  these  movements  in  the 
average  case,  and  when  used  on  the  Simplex  articulator 
require  practically  no  grinding.  When  the  Adaptable  is 
used  the  teeth  will  require  grinding  in  proportion  as  the 
adjustments  vary  from  the  average. 

Relations  of  the  upper  and  lower  teeth  on  the  left  side 
in  working  contact,  are  shown  in  Figure  167.  The  rela- 
tions of  the  teeth  on  the  same  side,  in  balancing  contact, 
are  shown  in  Figure  168. 


194 


Fig.  170 

How  to  Move  the  Articulator  Properly. 

There  are  correct  and  incorrect  ways  of  moving  the 
hows  of  the  Adaptable  and  Simplex  articulators  from  sidG 
to  side,  in  arranging  teeth.  If  the  incorrect  way  is  fol- 
lowed, the  articulator  will  be  of  little  use. 

Hold  the  articulator  above  and  below,  as  it  is  here  shown 
in  the  right  hand.  This  holds  the  Incisor  Guide  Pin  in  con- 
tact with  the  Incisor  Guide  Incline  and  any  opposing  teeth 
lightly  in  contact.  Place  the  fore  part  of  the  ball  of  the 
thumb  of  the  other  hand  on  the  inner  side  of  the  artificial 
fossa  as  shown  at  "A"  (not  against  the  front  as  shown  at 
UB"),  and  make  pressure  outward,  downward  and  back- 
ward. This  forces  the  vertical  flange  of  the  fossa  against 
the  condyle  pin  and  compels  the  condyles  to  follow  the 
correct  downward  and  lateral  inclinations.  The  arrange- 
ment of  the  teeth  will  be  greatly  facilitated  it*  the  condyle 
is  compelled  to  follow  the  correct  path  every  time  the  ar- 
ticulator is  moved. 

Do  nnt  place  the  thumbs  against  the  front  ot'  the  two 
fossae  ;ii  one  time  to  make  side  to  side  movements,  lesl 
(me  sid(  be  pivoted  againsl  ;i  thumb  instead  of  following 
its  proper  path.  Use  both  thumbs  at  once  only  to  throw 
the  teeth  into  incising  relation. 

195 


™"*™i"*ji? 

[(^■e* 

iLj 

J      .^^^ 

J?   i 

Zl 

Fig.  171 


PiS.  173 


kgj 

%y 

\ 

Fig.  172 


Fig.  174 


Fig.  175 

For  description  see  the  page  following. 

196 


Arranging  the  Teeth.     The  Loweb  First 
Molar. 

Apply  ;i  cone  of  wax  to  ;i  lower  firs!  molar.  Open  the 
articulator  and  attach  the  molar  to  the  ridge  in  approxi- 
mately the  correct  position,  but  too  high.  ( 'lost'  the 
articulator,  forcing  the  molar  inward  the  ridge.     Guide  i1 

to  correct  occlusal  relations  with  the  uppers  as  in  Figure 
171.  Wax  the  molar  firmly  in  posit  inn.  Make  pressure 
on  the  right  fossa  of  the  articulator  as  described  for  Figure 
170  and  throw  this  molar  into  working  bite  with  the 
uppers,  as  in  Figure  17± 

A  black  line  has  been  drawn  along  the  buccal  ridge  of 
the  middle  cusp  of  the  lower  molar.  It  should  be  con- 
tinuous with  the  black  line  in  the  buccal  groove  of  the 
upper  molar.  The  break  in  the  line  in  Figure  172  shows 
that  the  lower  molar  is  too  far  forward  for  articulation. 
Figures  171  and  172  show  that  teeth  may  be  in  good  posi- 
tion for  occlusion  without  being  in  position  to  articulate. 

In  figure  17-"I  the  lower  molar  has  been  moved  back- 
ward so  that  the  black  line  is  continuous  with  the  line  on 
the  upper,  in  working  bite,  but  the  buccal  cusps  do  not 
interdigitate  with  the  upper  cusps.  Errors  of  this  kind 
can  usually  be  corrected  by  depressing  the  buccal  cusps  of 
the  upper  molar,  but  in  this  case  the  steep  descending  in- 
clination of  the  condyle  path,  with  the  slight  lateral  incli- 
nation, necessitated  grinding  the  teeth  to  a  deeper  l>ite. 

With  a  fine  grit  inverted  cone  stone  the  mesial  marginal 
ridge  of  the  upper  molar  and  the  distal  marginal  ridge  of 
the  lower  molar  were  ground  until  they  could  be  properly 
interdigitated.     This  grinding  is  shown  in   Figure  171. 

In  Figure  175  the  mojars  are  shown  in  working  bite 
after  deepening  of  the  sulci  by  grinding  has  been  completed 
and  the  lower  molar  reset  to  proper  contact  with  the  upper. 
The  -pace  between  the  upper  second  bicuspid  and  the  low<  r 
molar  in  Figure  17-">  has  been  decreased  by  deepening  the 
bite  of  the  molars  and   raisins  the  lower  molar. 


197 


Fig.  176 


Fig.  178 


Fig.  1  77 


Fig.  179 


Fig.  ISO 

For  description  see  page  following. 

198 


Arranging  the  Teeth.-    The  Loweb  First 
Molar.    Continued. 

The  lower  first  molar  in  Figure  L76  is  in  the  same 
position  on  the  ridge  thai  ii  occupied  in  Figure  17.">,  but 
the  articulator  has  been  moved  so  as  to  throw  this  side  into 
balancing  relation.  The  triangular  ridge  of  the  mesio- 
lingual  cusp  of  the  upper  molar  should  slide  in  the 
disto-buccal  groove  of  the  lower  molar,  along  the  white 
lines  of  contact  "In  Balancing  Bite"  in  Figure  160,  but 
cusp  and  groove  are  separated  by  a  slight  space.  A  defect 
dt'  this  kind  can  usually  be  corrected  by  depressing  the 
lingual  cusp  of  the  upper  molar  until  contact  is  established 
and  waxing  the  upper  firmly  in  that  position.  It  may  be 
necessary  to  rotate  either  the  upper  or  the  lower  on  its 
vertical  axis  until  the  cusp  works  smoothly  in  the  groove. 

Examine  the  working  bite  articulation  from  the  lin- 
gual, as  shown  in  Figure  177.  The  slight  prominence  of 
the  mesio-lingual  cusp  of  the  lower  molar,  indicated  by  the 
arrow,  prevents  correct  relations  in  the  working  bite. 
Grind  this  away  with  the  inverted  cone  stone,  being  care- 
ful to  maintain  the  original  inclination  of  the  cusp  planes. 
Do  not  grind  a  flat  surface  on  the  tip  of  the  cusp.  After 
grinding,  raise  the  lingual  cusp  of  the  lower  molar  until  it 
takes  the  relation  of  the  upper  shown  in  Figure  178,  when 
in  working  bite. 

The  upper  and  lower  molars,  in  occlusion,  should  mesh 
as  in  Figure  179.  The  buccal  cusp  of  the  lower  should  till 
the  V-shaped  longitudinal  groove  between  the  lingual  and 
buccal  cusps  of  the  upper.  The  lingually  inclined  plane 
on  the  lower  buccal  cusp  should  be  in  contact  with  the 
buccally  inclined  plane  of  the  lingual  cusp. 

Figure  ISO  shows  the  relation  of  the  upper  and  lower 
molars  in  working  bite. 


199 


Fig.  181 


Pig.  182 


Arranging  the  Teeth. — The  Bicuspids. 

After  completing  the  articulation  of  the  upper  and  lower 
molars  for  the  case  here  illustrated,  the  distal  marginal 
ridge  of  the  upper  second  bicuspid  was  ground  in  the  man- 
ner described  for  the  first  molars  until  the  buccal  cusp  of 
the  bicuspid  could  be  brought  down  in  contact  with  the 
buccal  cusp  of  the  lower  molar  when  in  working  bite  rela- 
tion. The  tooth  was  then  examined  from  the  lingual  and 
adjusted  to  mesh  properly  with  the  lower  molar  in  working- 
bite. 

Attach  a  cone  of  wax  to  the  neck  of  the  lower  second 
bicuspid  and  place  it  on  the  ridge  in  the  manner  described 
for  the  molar  and  with  a  spatula  press  it  into  approximate 
occlusion  with  the  upper  second  bicuspid.  Move  the  artic- 
ulator so  as  to  test  the  articulation  in  working  bite,  which 
is  shown  in  Figure  182,  and  in  balancing  bite.  When  the 
lower  second  bicuspid  has  been  properly  articulated  with 
the  upper  second  bicuspid,  move  the  upper  first  bicuspid 
into  proper  articulating  relations  with  the  lower,  as  shown 
in  Figure  182. 

The  space  between  the  lower  second  bicuspid  and  the 
molar  in  Figure  182  will  exist  whenever  the  conditions  of 
the  case  necessitate  a  compensating  curve  of  more  than 


soo 


average  Bteepness.  The  existence  of  such  spaces  compen- 
sates, in  part,  for  the  shrinkage  of  rubber  in  vulcanizing 
and  reduces  the  liability  of  error  from  the  teeth  hcing 
forced  into  improper  contact  through  thai  shrinkage. 

Set  the  lower  first  bicuspid  for  occlusion  and  then  for 
articulation  by  the  methods  described.  Arrange  the  lower 
first  molar  and  the  bicuspids  of  the  opposite  sjde,  using 
the  same  technic.  Do  not  set  the  lower  second  molars  unl  il 
the  arrangemenl  of  the  teeth  has  been  tested  in  the  month 
and  proven  satisfactory. 

Set  the  lower  six  anteriors  to  approximate  positions  to 
determine  whether  they  meet  the  requirements  of  the  case 
as  to  width  and  length.  If  insufficient  space  exists  between 
the  lower  bicuspids  to  permit  setting  the  lower  anteriors 
because  of  irregularities  in  the  alignment  of  the  upper 
anteriors,  additional  space  may  be  made  by  grinding  the 
distal  sides  of  the  lower  cuspids  or  the  mesial  sides  of  the 
lower  first  bicuspids.  If  sufficient  space  cannot  be  pro- 
vided by  such  grinding,  or  if,  because  of  the  necessity  of 
setting  the  lower  incisors  directly  above  the  lower  ridge,  an- 
teriors considerably  narrower  than  those  regularly  carded 
with  the  uppers  are  required,  select  anteriors  of  the  next 
smallest  size  in  the  same  form,  using  the  Mould  Guide  il- 
lustrated on  page  116.  If  no  Mould  Guide  is  available  turn 
to  the  table  of  dimensions  of  anteriors  on  page  115.  In 
the  left  hand  column  locate  the  number  of  the  mould  being 
used.  In  the  column  headed  "Width  of  six  anteriors,  set 
up,"  learn  the  combined  width  of  these  lower  anteriors. 
By  means  of  the  dimensions  in  the  second  and  third  col- 
umns, determine  upon  anteriors  of  the  length  and  as  much 
narrower  as  seem  necessary.  Order  the  desired  teeth  by 
means  of  the  mould  number  which  will  be  found  on  the 
same  line  in  the  column  at  the  left. 

In  cases  requiring  anteriors  much  shorter  than  those 
regularly  carded  with  the  uppers,  they  may  be  found 
among    .Moulds  3B,  3C,  3D,    Hi,  or   1C 


201 


Pig.  183 


Fig.  184 


Fig.  185 


Fig.  186 


/  I. 


Fig.  188 


Fig.  187 


202 


Arranging  the  Teeth.— The  Cuspids. 

Adjust  the  upper  cuspid  to  the  Lower  firs!  bicuspid.  It 
is  generally   accessary   to  grind  the  mesial  slope  of  the 

buccal  cusp  of  the  lower  bicuspid  and  the  distal  slope  of 
the  cutting  edge  of  the  cuspid  to  permit  establishing  cor- 
rect relations. 

The  upper  latera]  adjoining  the  cuspid  should  be  re- 
moved from  its  place  without  beating  the  wax,  so  thai  it 
can  be  easily  replaced.  This  will  facilitate  articulating 
the  lower  cuspid,  as  iu  Figure  L83. 

Grind  the  mesial  slope  of  the  cutting  edge  of  the  upper 
cuspid  to  locate  the  tip  of  that  tooth  just  anterior  to  the 
mesial  contact  point  of  the  lower  bicuspid.  The  facet  thus 
established  must  not  be  inclined  lingually,  hut  must  he  a' 
righl  angles  to  the  long  axis  of  the  tooth.  The  tendency  in 
grinding  this  facet  is  to  incline  it  too  steeply  from  the 
mesial  to  distal,  making  the  cuspid  too  pointed  and  in- 
creasing the  difficulty  of  articulating  it  with  the  lower 
teeth.  The  mesio-distal  inclination  of  the  facet  on  the 
mesial  half  of  the  tooth  should  he  practically  parallel  to 
the  mesio-distal  inclination  of  the  buccal  cusps  of  the  upper 
bicuspids,  as  shown  in  Figure  184. 

Set  the  lower  cuspid  in  position  and  grind  the  mesio- 
distal  inclination  of  the  distal  half  of  the  cutting  edge, 
to  be  parallel  to  the  inclination  of  the  cutting  edge  of  the 
mesial  half  of  the  upper  cuspid  as  in  Figure  185. 

The  facet  on  the  mesial  slope  on  the  upper  cuspid  is  to 
he  ground  to  the  lingual  inclination  shown  by  the  outline 
in  Figure  L86,  so  that  a  straight  edge  placed  in  contact 
with  the  facet  will  touch  the  wax  at  the  mesio-lingual  cusp 
of  the  lirst  molar.  Grind  the  facet  on  the  distal  slope  of 
the  cutting  edge  of  the  lower  cuspid  to  a  labial  inclination 
which  is  the  complement  of  the  lingual  slope  o\'  the  upper 
cuspid  with  which  it  occludes,  as  shown  in  Figure  187. 
The  inclinat  ion  of  the  long  axis  of  each  lower  cuspid  is  also 
shown  in  Figure  1ST. 

203 


In  the  upper  part  of  Figure  187  the  complementary  in- 
clination of  the  facets  on  the  cutting  edges  of  the  cuspids  is 
shown  with  the  cuspids  in  occlusion.  In  the  lower  part  of 
the  Figure  the  cuspids  are  shown  in  articulation  with  the 
lower  about  to  begin  the  return  from  an  extreme  lateral 
excursion.  The  complementary  inclinations  of  the  facets 
make  it  possible  for  the  cuspids  to  remain  in  contact 
throughout  these  movements.  This  form  of  articulation  by 
the  cuspids  is  very  important  in  maintaining  the  stability 
of  the  dentures  and  in  protecting  the  upper  laterals  from 
breakage.  If  the  lower  cuspids  are  set  to  too  deep  an 
underbite,  the  dentures  are  almost  sure  to  be  tipped  out  of 
position  by  improper  cuspid  contacts ;  the  force  of  the 
closure  will  be  brought  upon  the  thin  edged  laterals  which 
are  not  fitted  to  stand  it,  and  they  will  be  broken  from  the 
plate.  This  form  of  improper  contact  is  very  apt  to  occur 
in  finished  dentures  unless  guarded  against  and  is  dis- 
astrous. 

Replace  the  upper  lateral  but  do  not  attach  it.  Move 
the  articulator  to  produce  the  working  and  balancing  rela- 
tions and  grind  the  mesial  edge  of  the  lower  cuspid  so  that 
it  clears  the  slope  on  the  distal  angle  of  the  upper  lateral 
as  in  Figure  185.  The  upper  laterals  and  the  lower  cuspids 
should  not  come  into  contact  in  any  movement  of  the  jaw. 

The  facet  on  the  cutting  edge  of  the  upper  lateral  should 
incline  upward  and  backward  more  than  that  on  the  edge 
of  the  cuspid,  as  is  shown  in  Figure  188.  When  this  facet 
has  been  ground,  articulate  the  lower  lateral  with  it.  Do 
not  grind  facets  on  the  cutting  edges  of  the  lower  incisors. 
Grind  facets  on  the  edges  of  the  upper  centrals  to  the  incli- 
nations shown  in  Figure  188  and  articulate  the  lower  cen- 
trals with  them. 

The  lower  incisors  should  be  set  with  the  necks  directly 
over  the  ridge  and  the  long  axis  of  the  teeth  should  be  in- 
clined as  is  shown  in  Figure  188. 

Figure  185  shows  the  lower  cuspid  in  occlusal  contact 
with  the  upper  cuspid  but  not  with  the  lateral. 

204 


Fig.  180 

Arranging  the  Teeth. — The  Incising  Bite. 

Before  trying  the  teeth  in  the  month  hold  the  articulator 
in  the  incising  position  shown  above  and  slightly  alter 
the  arrangement  of  the  incisors  and  cuspids  if  necessary 
so  that  they  will  come  into  proper  contact. 

The  upper  centrals  should  touch  the  lower  centrals  as 
shown.  The  upper  laterals  may,  in  certain  arrangements, 
i ouch  the  lower  laterals,  but  they  should  not  touch  the 
lower  cuspids.  All  instances  of  broken  laterals,  not  dne 
to  careless  handling,  which  have  come  to  the  attention  of 
the  writers  have  been  found  to  be  due  to  a  cuspid  striking 
the  lateral  in  the  incising  or  the  working  bite. 

The  lower  cuspids  should  touch  the  upper  cuspids  but 
nut  the  upper  laterals  in  masticating  movements. 

When  the  lower  is  in  central  occlusion  the  lower  incisors 
and  possibly  the  lower  cuspids  should  not  be  in  contact. 
The  lower  incisors  should  not  be  allowed  to  supporl  the 
dentures  in  lateral  protrusive  movements  bul  should 
share  this  strain  with  the  bicuspids  and  the  cuspids.  The 
pressure  on  the  cuspids  should  be  heavier  than  on  the 
upper  laterals  or  the  lower  incisors. 

20:> 


Fig.  190 


The  Incising  Bite — Continued. 

The  danger  of  breaking  the  incisors  in  use  of  the  den- 
ture will  be  eliminated  if  the  foregoing  instructions  are 
observed  and  the  errors  seen  in  the  finished  denture  are 
corrected  by  grinding  with  a  stone  while  the  dentures  are 
examined  for  these  contacts  in  the  mouth. 

The  lower  first  bicuspid  should  be  in  contact  with  the 
upper  cuspid  which  acts  as  a  protector  for  the  upper 
lateral  and  prevents  the  incisors  from  receiving  any  ex- 
cessive strain.  The  tip  of  the  cusp  of  the  lower  second 
bicuspid  may  touch  the  tip  of  the  upper  first  bicuspid  cusp 
but  this  is  not  essential.  The  tip  of  the  upper 
second  bicuspid  should  come  into  contact  with  the  mesio- 
buccal  cusp  of  the  lower  first  molar.  The  lingual  cusps 
of  the  bicuspids  and  molars  also  'come  into  contact  in  the 
incising  bite  relation.  Occasionally  the  lingual  cusps  will 
touch  so  heavily  that  the  buccal  cusps  cannot  come  into 
contact.  If  any  cusp  rides  so  heavily  on  an  opposing  cusp 
as  to  prevent  the  teeth  from  coming  into  the  proper  rela- 
tion with  their  antagonists,  a  little  careful  grinding  will 
correct  the  trouble. 

206 


[nspecting  the  Trial  Dentures  i\  the  Mouth. 

II  the  plane  of  occlusion  bas  been  correctly  established 
and  the  bite  correctly  taken  there  remains  only  the  neces- 
sity for  determining  whether  the  arrangemenl  of  the  teeth 
especially  the  ten  anteriors  can  be  altered  so  as  to  improve 
the  patient's  expression  and  increase  the  natural  appear- 
ance of  the  dentures.  The  mosl  satisfactory  results  in 
this  respect  can  only  be  obtained  by  placing  the  dentures 
in  the  mouth  and  engaging  the  patient  in  conversation  or 
by  having  the  patienl  read  aloud  while  watching  the 
appearance  of  the  teeth  and  the  patient's  expression  as  tho 
lips  and  mandible  move. 

Flic  esthetics  of  tooth  arrangemenl  is  largely  a  matter 
of  art  and  hence  no  hard  and  fast  rules  can  lie  laid  down 
governing  this  work.  The  following  suggestions  may  be 
found  of  assistance. 

Most  people  expose  all  or  nearly  all  of  the  length  of 
the  central  incisor  when  the  lips  are  retracted  in  a  broad 
smile  or  in  hearty  laughter.  The  edges  of  the  incisors 
in  the  feminine  type  usually  parallel  the  curvature  of  the 
lower  lip  while  in  the  masculine  type  they  tend  to  parallel 
the  straighter  line  of  the  upper  lip. 

The  upper  incisors  normally  show  more  than  the  bicus- 
pids so  that  their  tips  appear  to  be  set  at  a  lower  level 
than  the  tips  of  the  bicuspids.  Tn  most  artificial  dentures 
the  reverse  condition  exists. 

The  upper  lip  rarely  comes  in  contact  with  the  bicus- 
pids when  the  lip  is  retracted  in  smiling;  a  space  exists 
between  the  bicuspids  and  the  lip  during  this  action  which 
casts  a  shadow  over  these  teeth  tending  to  decrease  their 
conspicuousness. 

The  upper  bicuspids  are  set  so  that  they  do  not  touch 
the  lip  when  the  patienl  smiles,  the  arch  is  narrowed, 
usually  resulting  in  a  marked  improvement  in  speech. 
This  arrangemenl  of  the  upper  bicuspids  assists  in  giving 
stability  to  the  lower  denture  by  bringing  the  lower  bi- 
cuspids more  directly  over  the  crest  of  the  lower  ridge. 

207 


Inspecting  the  Trial  Dentures  in  the 
Mouth — Continued. 

When  looking  at  the  bicuspids  of  a  patient  whose  lip 
is  raised  as  in  smiling,  from  a  point  directly  in  front  of 
the  patient,  it  will  often  be  fonnd  that  the  amount  of 
bicuspid  showing  depends  largely  on  the  type  of  the  pa- 
tient's face.  The  bicuspids  are  usually  most  visible  in 
faces  of  the  ovoid  type  and  less  visible  in  the  mouths  of 
patients  who  have  square  and  oval  faces  and  least  promi- 
nent in  faces  that  are  markedly  tapering  in  type. 

The  curve  of  the  upper  alveolar  ridge  in  the  bicuspid 
region  may  be  used  as  an  aid  to  getting  the  proper  esthetic 
effect  for  the  bicuspids  by  setting  them  to  a  curve  that  par- 
allels the  curve  of  the  ridge. 

In  the  instructions  given  for  setting  the  anterior  teeth 
the  inclinations  given  were  for  the  average  case.  At  this 
time  it  may  be  possible  to  improve  the  patient's  appear- 
ance by  altering  the  inclinations  of  the  various  teeth  to  suit 
the  requirements  of  the  case  presenting  or  to  increase  or 
decrease  the  prominence  of  the  laterals  or  of  the  cuspids. 

The  lower  anteriors  should  be  kept  .over  the  crest  of  the 
lower  ridge  to  let  the  lower  lip  fall  to  an  almost  vertical 
position.  The  upper  centrals  may  be  brought  forward  to 
carry  the  upper  lip  to  a  position  where  the  upper  lip  is 
more  prominent  than  the  lower,  which  is  normal. 

Where  conditions  permit,  the  roll  effect  often  seen  on 
the  lower  lip  can  he  had  if  the  upper  incisors  just  touch 
the  inner  edge  of  the  lower  lip  when  the  mandible  is  at 
rest  with  the  occlusal  surfaces  of  the  dentures  slightly 
separated. 

When  the  arrangement  of  the  teeth  has  been  accom- 
plished in  a  satisfactory  way  soft  wax  may  be  added  to 
the  labial  flanges  of  the  upper  and  the  lower  dentures 
till  the  desired  fullness  of  the  upper  lips  and  cheeks  is 
obtained. 

208 


Arranging  the  Teeth     Lo\i  i  i;  Second  Molars 

Th(    -         _        "lui  lower  second  molars  is  left  till  the 
-    they  are  the  teeth  principally  affected  when  a 
•  compel  -        _  curve  is  developed,  and  requi]    - 
grinding,     [f  s  a  curve  without  proper  grinding  they 

influence  the  motion  of  the  articulator  and 
re  with  th<  manipulation  of  it. 

When  the  "try-in"  is  complete  and  all  relations  are  satis- 
.  s       he  1-nvor  second  molars  and  articulate  them  in 
the  manner  described  for  the  other  teeth.     Occasionally  the 
lingnal  cusps  of  the  upper  second  molars  will  ride  heavily 
in  the  disto-bnccal  grooves  of  the  lower  second  molar  in  the 
balancing  relation  so  that  they  interfere  with  the  correct 
relati      -        the  other  teeth  in  articulation.     This  is  espe- 
cially apl  ccur  when  a  steep  compensating-  curve  is 
lished.     To  correct  this,  use  the  inverted  cone  carbo- 
rundum stone  and  deepen  the  disto-bnccal  groove  of  the 
lower  molar  and  flatten  the  slope  of  the  buccal  incline  of 
the  lingual  cusp  of  the  upper  second  molar  till  the  bicus- 
-  and  first  molars  of  both  sides  assume  correct  relations. 
When  the  Simplex  articulator  is  used  it  is  better  to  grind 
the  lingual  cusps  of  the  upper  second  molar  and  the  groove 
e  lower  second  molar  so  that  these  teeth  cannot  touch 
in  the  balancing  bite  relation  rather  than  to  permit  them 
heavily. 
The  curve  made  by  the*  occlusal  surface  of  the  lower 
mol;    -           -        id  bicuspids  should  be  governed  at  least 
in  part  by  the  curvature  of  the  posterior  portion  oi  the 
lower  ridge      1:  the  occlusal  surfaces  of  the  lower  molars 
are  set  parallel  to  this  section  of  the  ridge,  the  force  ap- 
plied through  the  teeth  in  the  act  of  masticating  will  be  al 
right  ans     -        the  surface  of  the  ridge,  and  the  pressure 
will  thereby  seat  the  lower  denture  rigidly  in  {dace  and 
will                 a  tendency  of  the  lower  to  move.     A  lower 
ridge  that  has      _         curve  will  call  for  a  correspondingly 
great   curvature   in   the  arrangement   of   the  molars   and 
bicus] 

COO 


_, 


Fig.  191 

Arranging  the  Teeth. — The  Lower  Second 
Molars — Continued. 

In  practice  the  curvature  of  the  lower  molars  must  be 
modified  to  meet  the  requirements  of  the  upper  set  for 
stability.  In  many  cases  a  curvature  great  enough  to 
stabilize  with  the  lower  will  tend  to  create  a  forward 
pressure  on  the  upper  which  would  dislodge  it.  If  the 
upper  ridge  is  flat,  set  the  bicuspids  and  molars  to  develop 
a  curve  (b)  which  will  be  half  way  between  the  flat- 
ness of  the  upper  (a)  and  the  steepness  of  the  lower  (c). 

Bear  in  mind  that  as  the  curve  that  is  indicated  in  the 
Figures  163  and  164  is  departed  from  the  necessity  for 
orindine'  increases. 


210 


Part  Y 

The  Simplex  Articulator 

and 

The  Snow  Face  Bow 


The  Simplex  Articulator  and  Accessories. 

Dentists  who  do  not  wish  to  use  the  Adaptable  articu- 
lator will  find  the  Gysi  Simplex  articulator  satisfactory. 
It  requires  no  measurements  of  patient's  jaw  movements 
and  no  adjustments.  The  rotation  points  are  fixed  in  the 
positions  necessary  to  reproduce  the  average  downward 
and  lateral  inclinations  of  the  condyle  paths  as  carefully 
recorded  by  Prof.  G-ysi  in  400  cases.  The  upper  bow  is 
supported  by  an  Incisor  Guide  Pin  as  in  the  Adaptable. 

The  Simplex  articulator  is  used  by  many  dentists  with- 
out the  accessories,  shown  in  Figure  192,  but  the  use  of 
the  Face  Bow  and  the  accessories  will  enable  them  to  avoid 
errors  which  might  otherwise  pass  unrecognized  and  will 
result  in  a  higher  average  of  satisfaction  to  both  patients 
and  dentists  than  could  be  achieved  without  their  use.  The 
average  time  required  by  the  technic  to  be  described,  about 
30  minutes  when  the  technic  has  been  mastered,  is  negli- 
gible as  compared  with  the  time  which  would  be  lost  if 
unrecognized  errors  necessitated  remaking  the  case. 

The  use  of  the  Snow  Face  Bow  enables  the  dentist  to 
mount  the  impressions  and  bites  in  the  same  relation  to 
the  centers  of  motion  in  the  articulator  that  they  occupy 
to  the  centers  of  motion  of  the  j  aw. 

The  supreme  importance  of  taking  correct  bites  justifies 
the  use  of  the  Incisor  Path  Marker  and  the  Horseshoe 
Plate  and  the  Slip  Joint  Stem. 


Building  Separate  Bite  Plates. 

If  the  impressions  are  not  to  be  used  for  taking  the 
bites,  it  will  be  necessary  to  pour  casts  as  described  for 
Figure  132,  to  shape  over  them  base  plates  as  described 
for  Figure  151,  to  build  a  bite  rim  upon  the  upper  base 


212 


ujL  J -4)  k 


Fig.  102 

THE  GYSI   SIMPLEX  ARTICULATOR   OUTFIT  COMPRISES 

A  Gysi  simplex  Articulator  "A"  composed  of  1  Articulating  Frame,  in 
two  parts,  1  upper  and  1  lower  -Model  Support,  1  Straight  Incisor  Guide 
I  'in  "B",  two  Face  Bow  adapters  of  the  articulator  "N".  An  Incisor 
Guide  incline   "I". 

Aii  Incisor  Guide  "C"  for  mounting  casts  on  the  articulator  when  t ho 
Face  Bow  is  not  used. 

A  Snow  Face  How.  "D"  with  condyle  roils  "P  P"  and  lock  nuts  "K  R" 
and  a  Cylindrical  Block  "\Y". 

A  Horseshoe  Plate  "E"  and  Slip  Joint  Stem  "F".  The  Horseshoe  Plate 
is  used  with  the  Incisor  Path  Marker  to  obtain,  correct  bites.  The  Slip 
Joint  stem  connects  the  Horses! Plate  with  the  Face  Bow. 

A  Mouth  Piece  for  the  Face  Bow  "II"  used  only  when  mash  bites  are 
taken. 

\  Curved  Incisor  Guide  Pin,  "I"  used  only  while  mounting  casts  with 
t  he  Face  Bow. 

An  Incisor  Path  Marker.  "K"  used  with  the  Horseshoe  Plate  for  de- 
termining correct    bites. 

An  Anterior  Supporting  Block,  "L"  to  support  the  front  of  the  Face 
Bow  when  mount  Ing  i  ast s. 

Two  Bite  Lock  Trays  "M"  for  locking  bites  together. 

plates,  adapting  the  technic  described  for  Figure  1."-".  to 
take  the  bite  with  base  plate  bite  rims,  using  the  technic 
described  for  the  impression  bite  rims  beginning  <>n  page 
137. 


213 


Fig.  193 


Attaching  the  Horseshoe  Plate. 

Both  bites  are  in  the  mouth.  Attach  the  horseshoe  plate 
to  the  slip-joint  stem  and  hold  it  so  that  the  pins  rest 
upon  the  occlusal  surface  of  the  lower  bite  rim  and  about 
Y2  inch  of  the  Horseshoe  Plate  projects  in  front  of  the 
upper  bite  rim  when  it  is  closed  upon  the  lower.  See  that 
the  Slip  Joint  Stem  projects  forward,  about  in  the  median 
line.  Have  the  patient  close  and  impress  the  points  of  the 
pins  on  the  occlusal  surface  of  the  lower.  Remove 
the  Horseshoe  Plate  and  lower  bite  rim.  Detach  the  Slip- 
Joint  Stem  and  set  the  Horseshoe  Plate  on  the  lower  bite 
rim  as  described  for  Figure  108.  Equalize  the  biting 
strain  as  described  for  Figure  109.  Attach  the  Incisor 
Path  Marker  to  the  upper  bite  rim  as  described  for  Figure 
113.  Make  the  crosses  on  the  face  as  described  for 
Figure  106. 

214 


^K 


^* 


% 


f 


'J 


Fig.  104 

Adjusting  the  Face  Bow  to  the  Face.    Part  1. 

Push  the  right  condyle  rod  as  far  inward  as  it  will  go 
and  lock  it  there.  Place  the  inner  end  of  this  condyle  red 
over  the  intersection  of  the  lines  over  the  right  condyle. 
Push  the  other  condyle  rod  gently  hut  firmly  against  the 
face,  with  its  inner  end  over  the  left  condyle,  and  lock  it 
there. 

Count  the  notches  external  to  the  sleeve  of  the  lock  mil 
on  the  condyle  rod  on  the  patient's  left.  Remove  the 
Face  Bow  from  the  i:\cv.  Divide  the  number  of  notches 
which  were  external  to  the  sleeve  of  the  lock  nut  on  the 
left  by  2.  Adjust  each  condyle  rod  so  that  half  of 
the  total  notches  exposed  on  the  left  rod  are  external  to  the 
sleeve  of  each  lock  nut,  when  the  nut  is  tightened.  This 
insure-  centering  the  Face  Bow  when  it  i<  replaced  upon 
the  face. 


215 


r       / 

Fig.  195 

Adjusting  the  Face  Bow  to  the  Face.    Part  2. 

Carry  the  Face  Bow  to  position  on  the  face,  beginning 
with  the  condyle  rods  at  the  level  with  the  angles  of  the 
jaw  as  shown  in  Figure  195.  Move  them  upward  and 
slightly  backward  to  their  positions  over  the  crosses.  The 
pressure  exercised  upon  the  face  by  the  condyle  rods  should 
be  sufficient  to  aid  in  holding  them  in  position,  but 
should  not  be  painful  to  the  patient.  If  only  a  slight 
adjustment  of  the  condyle  rods  is  necessary  to  achieve  this 
effect,  it  can  be  made  on  one  side.  If  much  adjustment 
must  be  made,  it  should  be  divided  between  the  two  sides. 
Lay  the  Face  Bow  aside  until  the  incisor  path  record  has 
been  taken.  Take  this  record  as  described  beginning  with 
Figure  115. 

216 


Taking  the  [ncisob  Path  Record. 

Attach  the  [ncisor  Path  Marker  to  the  labial  surface  of 
the  upper  bite  rim  in  the  median  line,  in  such  position 
that  when  the  spring  controlling  the  pin  is  released  onlv 
the  cone  of  the  Marker  projects  below  the  incisal  edge,  as 
illusl  rated  in  Figure  1 13. 

I  Slacken  the  anterior  portion  of  the  upper  surface  oi 
the  Eorseshoe  Plate  as  described  for  Figure  114,  and 
lightly  coat  it  with  wax.  Place  the  lower  impression  and 
Horseshoe  Plate  in  the  mouth  and  make  the  incisor  path 
record  as  described  for  Figure  115.  When  the  jaw  is  at 
rest  and  the  point  of  the  Incisor  Path  Marker  is  in  the 
point  of  the  incisor  path  record,  the  bite  is  correct. 

While  the  point  of  the  Incisor  Path  Marker  rests  in 
the  anterior  point  of  the  incisor  path  record,  make  ver- 
tical marks  across  the  buccal  surfaces  of  both  bite  rims 
as  illustrated  on  the  left  in  Figure  125.  Lock  the  pin  of 
the  Incisor  Path  Marker  in  a  raised  position.  Deepen  the 
vertical  line  across  the  buccal  surface  of  the  bite  rim  into 
notches  as  illustrated  on  the  right  in  Figure  125. 

While  the  use  of  this  incisor  path  record  in  connection 
with  the  Simplex  articulator  does  not  permit  of  any 
adjustment  of  the  articulator  to  reproduce  habitual  jaw 
movements,  it  is  invaluable  because  it  is  the  onlv  known 
means  of  determining  accurately  when  bites  are  correct 
in  all  horizontal  relations.  This  is  one  of  the  steps  where 
what  appears  at  a  casual  glance  to  lie  a  waste  of  time  will 
generally  prove,  in  the  end.  to  be  an  economy  of  time, 
because  of  the  avoidance  of  errors  otherwise  undetectable. 
It  will  be  well  to  review  what  has  been  offered  in  connec- 
tion with  the  taking  of  the  bite  by  this  method  on  page  140. 


21' 


Fig.  196 

Adjusting  the  Face  Bow  to  the  Face.  Part  3. 

With  both  bite  rims  and  the  Horseshoe  Plate  in  the 
mouth,  and  with  the  point  of  the  Marker  in  the  point  of 
the  incisor  path  record,  place  the  Slip  Joint  Stem  upon 
the  rods  of  the  Horseshoe  Plate.  Insert  the  outer  end 
of  the  Slip  Joint  Stem  into  the  hole  of  the  cylindrical 
block  on  the  arch  of  the  Face  Bow.  Pass  the  Face  Bow 
about  the  face  in  the  position  shown  in  Figure  196  and 
move  the  condyle  rods  upward  and  backward  to  their  posi- 
tions over  the  crosses.  Hold  the  Face  Bow  in  this  position 
and  lightly  set  the  lock  screw  of  the  cylindrical  block. 
Examine  on  both  sides  of  the  face  and  make  sure  that  the 
condyle  rods  of  both  sides  are  over  the  crosses.  Then  lock 
the  set-screw  of  the  cylindrical  block  so  firmly  that  no 
change  in  the  relation  of  the  Face  Bow  to  the  bite  rim  can 
occur  during  the  following  manipulation. 

218 


Fig.  197 

Removing  the  Face  Bow  . 

Loosen  the  lock  nuts  of  the  condyle  rods  and  move 
them  outward,  away  from  the  face  as  shown  here.  Place 
the  thumh  and  lirsi  finger  on  the  opposite  sides  of  the 
anterior  margin  of  the  Horseshoe  Plate  with  the  hand 
below  the  Face  Bow  as  shown.  Place  the  inner  side  of  the 
tip  of  the  third  finger  againsl  the  face  side  of  ihe  cylin- 
drical block  and  press  ii  upward  while  pinching  the 
sides  of  the  Horseshoe  Plate.  This  action  will  force  the 
Slip  Joint  from  the  Horseshoe  Plate.  Lay  the  Face  Bow 
aside  until  it  is  needed  for  mounting  the  cast  upon  the 
articulator.  Take  the  bite  lock  impressions  as  described 
for  Figure  126.  Prepare  impressions  for  making  casts 
and  make  the  casts  as  described,  beginning  on  page  L55. 
Fasten  the  bites  together  with  the  Bite  Locks  as  described 
for  Fisrure  138. 


219 


V~'*msik~ \  <|W 


Pig.  198 

Mounting  Casts  on  the  Simplex  Articulator 
With  a  Face  Bow,    Part  1. 

The  articulator  is  here  shown  with  the  hite  rims  fas- 
tened together  by  the  Bite  Locks  "M"  and  mounted  on 
the  Horseshoe  plate  "E"  and  the  Slip  Joint  Stem  "F" 
which  passes  through  the  cylindrical  block  of  the  Face 
Bow  "W".  The  Condyle  Bods  of  the  Face  Bow  "P"  are 
over  the  Face  Bow  adapters  of  the  articulator  "1ST".  The 
Curved  Incisor  Guide  Pin  "I"  is  in  place.  The  Anterior 
Supporting  Block  receives  both  the  Slip  Joint  Stem  "F" 
and  the  Straight  Incisor  Guide  Pin  aB"  and  its  set  screw 
is  locked  to  support  the  Horseshoe  Plate  and  Slip  Joint 
Stem  parallel  with  the  table.  The  notch  "S"  on  the  frame 
of  the  articulator  locates  the  proper  level  of  the  occlusal 
plane  when  the  Face  Bow  is  not  used. 

The  technic  for  mounting  bites  and  casts  on  the  Simplex 
Articulator  by  means  of  the  Snow  Face  Bow  is  given  on 
the  next  page. 


220 


Mounting  Casts  <>\  the  Simplex  Aeticulatob 
With  a  Face  How.     Part  2. 

The  Simplex  articulator  is  a  little  wider  than  the  ar- 
ticulator for  which  the  Face  Bow  was  designed.  It  is 
therefore  necessary  to  arrange  the  condyle  rods  to  accom- 
modate this  additional  width.  This  may  be  done  by  set- 
ting both  condyle  rods  in  the  Face  Bow  in  such  way  thai 
one  notch  and  balf  the  distance  to  the  next  one  is  external 
to  the  sleeve  of  the  lock  nnt,  or  by  adapting  it  to  the 
articulator  in  the  same  way  that  it  was  adapted  to  the 
face  in    Figure   196.      Tighten  the  lock  nuts. 

Replace  the  straight  Incisor  Guide  Pin  with  a  curved 
Incisor  Guide  Pin  and  see  that  the  top  of  the  pin  is  flush 
with  the  top  of  the  sleeve  in  which  it  is  held.  Lock  it 
in  this  position.  If  base  plates  and  bite  rims  were  \\^'(\ 
for  taking  biles  instead  of  the  impression  bite  rims,  tie 
t lie  casts  into  the  base  plate  bites  which  are  already 
mounted  on  the  Horseshoe  Plate  and  set  the  pins  of  the 
Horseshoe  Plate  firmly  into  the  Slip  Joint  Stem  of 
the  Face  How.  Spring  the  inner  ends  of  the  condyle  rods 
over  the  Face  Bow  Adapters  (cylindrical  projections  on 
the  articulator  external  to  the  beads  of  the  condyle  pins). 

The  anterior  part  of  the  Face  Bow  must  be  supported 
so  that  the  occlusal  plane  of  the  bite  rims  is  parallel  to 
the  flat  surface  on  which  the  articulator  rests.  This  may 
be  done  by  means  of  an  improvised  stop  for  the  cylin- 
drical bloc'-:  of  the  Face  Bow  or  by  means  of  the  Anterior 
Supporting  Block  shown  in  Figure  198.  The  projecting 
end  of  the  Slip  Joint  Stem  is  placed  through  the  large  hole 
in  the  Anterior  Supporting  Block  and  the  straight  Incisor 
Guide  Pin  of  the  articulator  is  placed  in  the  other  hole. 
"When  the  Slip  Joint  Stem  is  parallel  with  the  top  of  the 
table  tighten  the  set-screw  of  the  Anterior  Supporting 
Block,  which  locks  all  the  parts  in  thai  relation. 

Attach  the  casts  to  the  model  bows  using  the  technic 
described  for  Figures  L39,   1  tO  and  141. 


221 


Fig.  199 

Mounting  Casts  on  the  Simplex  Articulator 
Without  the  Face  Bow. 

Dentists  who  do  not  wish  to  employ  the  Face  Bow  may 
mount  casts  upon  the  Simplex  articulator  without  it,  but 
probably  not  with  the  same  freedom  from  error  as  when 
the  Face  Bow  is  used. 

If  a  line  from  the  center  of  the  vault  be  prolonged  up 
the  back  of  the  upper  cast  and  one  from  the  frenum  be 
prolonged  up  the  front  of  it  and  these  be  joined  by  a  line 
along  the  top  of  the  cast,  as  shown  in  Figure  198,  it  will 
be  easy  to  center  the  cast  laterally  under  the  upper  model 
bow.  The  antero-posterior  position  of  the  bite  rims 
should  be  such  that  the  incisal  edge  of  the  upper  bite  at 
the  median  line  will  be  about  l/o  inch  back  of  the  posterior 
side  of  the  Incisor  Guide  Pin. 

Lock  the  straight  Incisor  Guide  Pin  in  the  articulator 
so  that  its  top  is  flush  with  the  top  of  the  sleeve  by  which 
it  is  held.     Place  the  Incisor  Guide  on  the  Incisor  Guide 


Fig  200 


Mounting  Casts  ox  the  Simplex  Articulator 

Without  the  Face  Bow — Continued. 

Pin  with  its  point  facing  directly  backward  in  the  median 
line  and  lock  the  set-screw  into  the  depression  in  the 
straight  pin.  Place  an  clastic  band  around  the  set-screw  of 
the  Incisor  Guide  and  in  the  notches  on  the  outside  of  the 
vertical  pari  of  the  articulator  frame  "S",  Figure  192. 
The  occlusal  plane  of  the  bite  rim  should  he  on  a  level  with 
this  hand. 

Place  a  -on  mass  of  carding  wax  on  the  top  of  the  lower 
model  bow  and  press  the  lower  cast  down  upon  it  until  the 
occlusal  plane  of  the  bite  rim  is  level  with  the  elastic  hand, 
and  the  incisal  edge  of  the  upper  bite  rim  at  the  median 
line  touches  the  point  of  the  Incisor  Guide  or  is  about 
1  o  inch  back  of  the  posterior  surface  of  the  Incisor  Guide 
Pin,  and  adjust  the  casts  till  the  line  across  the  top  of  the 
upper  is  beneath  the  centre  i\\'  the  upper  how.  Attach  the 
cast  to  the  articulator  by  the  technic  described  for  Figures 
130,  140,  141. 


Face  Bow  Technic  for  Large  Cases. 


The  Simplex  articulator  is  built  on  the  average  of  a 
great  many  cases  and  is  therefore  smaller  than  the  larger 
cases  that  present.  This  difference  will  be  apparent  on 
large  cases  only  when  the  Face  Bow  is  used,  and  may  be 
overcome  by  the  following  technic. 

Adjust  the  Face  Bow  as  if  the  case  were  of  the  average 
size.  When  the  Face  Bow  is  locked  in  the  proper  relation 
to  the  face  remove  it  without 
loosening  the  adjustment  and 
apply  it  to  the  articulator,  in 
which  the  curved  pin  has 
been  placed.  If  the  posterior 
end  of  the  Slip  Joint  Stem 
(or  the  rim  of  the  bite  por- 
tion of  the  mouthpiece,  when 
that  is  used)  is  not  slightly 
distal  to  the  rear  of  the 
straight  sections  of  the 
curved  pin,  the  casts  will  be 
mounted  too  far  forward  in 

the  articulator  to  permit  of  correct  manipulation.  To 
make  the  proper  adjustment  note  the  distance  between  the 
rear  edge  of  the  block  of  the  Slip  Joint  Stem  and  the 
distal  surface  of  the  straight  sections  of  the  curved  pin. 
Make  a  short  line  on  the  side  of  the  face  extending  for- 
ward from  the  intersection  of  the  lines  marking  the  con- 
dyle location  and  parallel  to  the  plane  of  occlusion.  Space 
off  on  this  line  a  distance  equal  to  that  noted  when  examin- 
ing the  relation  of  the  Slip  Joint  Stem  to  the  articulator 
pin.  Make  a  similar  line  and  space  off  an  equal  distance 
on  the  opposite  side  of  the  face.  Readjust  the  Face  Bow 
to  the  new  marks  and  proceed  as  ■usual  from  this  point. 


Fig.  201 


224 


Part  VI 

Flasking,  Vulcanizing, 

Finishing 

and  Perfecting 

the  Fit 


Fig.  202 

Preparation  oe  Trial  Dentures  eor  Flashing. 

Part  I. 

Place  the  trial  dentures  correctly  on  the  casts  and  attach 
by  heating  the  edges.  Remove  loose  teeth  one  at  a  time, 
thoroughly  dry  the  teeth  and  wax  and  firmly  reset  the  teeth. 

Wax  the  labial  and  buccal  surfaces  adjacent  to  the  teeth 
to  a  greater  fullness  than  desired  in  the  finished  denture 
to  permit  of  finishing  and  polishing.  No  wax  should  be 
added  to  the  Dentsply  Baseplate  Composition  that  covers 
the  palate  of  the  upper  as  this  material  is  of  the  proper 
thickness  to  produce  a  thin,  strong  palate  of  uniform  thick- 
ness in  the  denture. 

It  is  best  to  have  the  buccal  surfaces  of  the  lower  convex 
where  possible,  especially  in  the  molar  region.  Concave 
surfaces  tend  to  make  it  difficult  for  the  tongue  to  sweep 
food  forward  to  a  position  where  it  can  be  carried  onto 
the  occlusal  surfaces  of  the  teeth  for  mastication. 

Fill  the  interproximal  spaces  with  wax  but  not  enough 
to  permit  the  teeth  to  be  dislodged  in  packing.  Wax 
should  be  added,  where  necessary,  in  a  plastic  condition 
and  worked  to  the  proper  contour  with  a  moderately  warm 
spatula.  Fluid  wax  may  warp  the  trial  denture  or  draw 
teeth  out  of  position  on  cooling. 

Do  not  carve  finished  gum  festoons  or  flow  the  surface 
of  the  wax  smooth.  This  may  cause  the  wax  to  change 
form  and  derange  the  articulation.  Final  contouring  and 
festooning  is  easily  done  with  a  vulcanite  finishing  bur 
as  described  later. 

226 


Fig.  203. 


Preparation  of  Trial  Dentures  fok  Flasking, 

Part  II. 

This  illustration  shows  the  tin  piece  to  reproduce  the 
rugae  in  place,  and  the  wax  in  which  the  incisors  and  cus- 
pids are  held,  carved  so  that  the  rubber  will  imitate  the 
full  natural  contour  of  the  lingual  surfaces  of  these  teeth, 
both  of  which  greatly  assist  in  articulation  of  words. 

When  the  wax  is  left  thick  at  the  point  where  it  is  being- 
cm  by  the  knife,  polishing  the  vulcanite  is  made  easier. 

The  extra  thickness  of  Dentsply  Baseplate  Composition 
across  the  heel  should  now  be  cut  away. 

This  illustration  shows  thai  the  extensive  grinding  neces- 
sitated by  the  rather  unusual  inclinations  of  the  condyle 
paths  in  this  case  has  not  altered  the  forms  of  the  teeth, 
and  their  masticating  power  has  not  been  reduced.  The 
secondary  cusps  have  not  been  destroyed  and  they  are  in 
position  to  permit  the  establishment  o['  the  numerous 
small,  sharp-edged  facets  essential  to  etlicient  mastication 
with  the  limited  power  it  is  possible  to  exercise  through 
artificial  dentures. 

The  final  grinding  in  the  mouth  will  he  illustrated  later. 


Pig.  204. 

Flasking  the  Dentures. 

Fill  the  cup  portion  of  a  B.D.M.  Co.  flask,  No.  22C, 
with  equal  parts  of  Spence  plaster  and  plaster  of  Paris, 
mixed  thick.  Imbed  the  cast  in  it  until  the  outer  edge  of 
the  extension  left  on  the  cast  is  about  level  with  the  flask 
rim.  Shape  the  investing  plaster  as  shown  in  the  illus- 
tration. When  the  plaster  is  hard  draw  on  it  a  pencil 
line  extending  entirely  around  the  cast  so  that  it  will 
everywhere  be  %  inch  distant  from  the  wax  or  baseplate. 
Coat  the  surface  of  the  plaster  with  thin  Sandarac  to  act 
as  a  separating  medium. 

Make  a  second  mix  of  equal  parts  of  Spence  plaster  and 
plaster  of  Paris  but  not  so  thick  as  the  first.  With  a  small 
spatula  work  some  of  it  carefully  into  the  crevices  between 
the  teeth,  as  illustrated  on  page  229.  Then  cover  the 
entire  wax  trial  plate  and  the  teeth.  Clean  the  rim  of 
the  cup  portion  of  the  flask,  place  the  ring  in  position 

228 


Flanking  the  Dentures,  Continued. 

upon  it,  and  till  the  ring  with  the  remainder  of  the  second 
mix.  Scat  the  lid.  Do  not  let  any  plaster  escape  between 
the  cup  of  the  flask  and  the  ring.  Place  the  thisk  in  ;i 
Donham  clamp  or  under  a  weigh.1  until  the  plaster  sets, 
[mmerse  the  flask  for  L5  minutes  in  a  dish  containing 
about  2  quarts  of  water  at  L18-1200  F,  when  the  wax  will 
ho  soft  enough  to  permil  opening  the  flask  withoul  danger 
of  breaking  the  cast.  If  the  baseplate  slicks  to  the  cast, 
soften  ii  by  directing  a  bunsen  flame  upon  it. 

A  small  colander  with  line  perforations  in  the  bottom 
will  he  found  convenient  tor  bolding  the  flask  while  wash- 
ing tin1  wax  away  from  the  cast  and  the  tooth.  To  pre- 
pare for  washing  away  the  wax,  add  carbonate  of  soda, 
usually  known  as  washing  soda,  to  actively  boiling  water 
in  proportion  of  one  tablespoonful  to  two  quarts  of  water. 
This  mixture  cms  wax  much  more  readily  than  plain 
water  and  leaves  the  teeth  very  clean.  Hold  the  colander 
above  the  vessel  in  which  the  mixture  is  boiling.  With  .1 
small  dipper  pour  some  of  the  boiling  solution  over  the 
surface  to  be  cleaned. 

229 


Fig-.  200. 


Preparation  of  Channel  for  Waste  Rubber. 

This  illustration  shows  a  section  of  a  flask  with  a  chan- 
nel cut  for  receiving  the  surplus  rubber. 

The  narrow  band  of  plaster  left  between  the  space  filled 
by  the  rubber  and  the  channel  facilitates  the  escape  of 
surplus  rubber  and  the  closing  of  the  flask  in  testing  for 
quantity;  and  keeps  the  rubber  under  pressure,  retaining 
in  the  denture  expanding  rubber  that  would  escape 
through  waste  gates  during  the  initial  period  of  vulcanizing. 

In  the  last  period  of  vulcanizing,  the  rubber  loses  vol- 
ume and  draws  away  from  the  teeth,  leaving  spaces  where 
fluid  food  may  lodge.  The  Snow  waste  channel  will  mini- 
mize error  caused  by  this  change. 

The  waste  channel  is  cut  with  a  Kingsley  scraper  up  to 
the  pencil  line  shown  on  page  228,  leaving  a  strip  of 
plaster  from  1/16"  to  %"  wide  between  the  rubber  space 
and  the  channel.  The  channel  may  extend  outward  to 
the  metal  flask  rim  and  should  be  about  1/g"  deep  at  its 
centre,  sloping  up  toward  the  narrow  plaster  rim  and  the 
edge  of  the  flask  from  this  point. 

230 


\v 


c 


) 


Pig.  207. 

Packing  and  Testing.,  Part  I. 

Heat  slowly  the  portion  of  the  flask  containing-  the  teeth 
until  the  teeth  become  so  hot  that  the  fingers  cannot  lie  held 
upon  them.  Fold  one  end  of  a  sheet  of  pink  rubber  to 
make  a  strip  V.  inch  wide  and  of  double  thickness.  Cut 
this  strip  crosswise  into  pieces  Y2  inch  long  and  a  little  Less 
I  ban  Yg  inch  in  width.  Place  one  end  of  one  of  these 
strips  in  each  interproximal  space  beginning  at  the  distal 
side  of  jhc  first  molar.  Allow  the  balance  of  the  strip 
to  extend  vertically  upward.  When  strips  have  been  placed 
between  all  of  the  teeth  up  to  the  mesial  of  the  opposite 
liist  molar,  return  to  the  first  one  placed  and  bend  it 
around  the  gingival  margin  of  the  tooth  into  the  next 
approxinial  space  ahead  "1'  it.  Repeat  this  until  the 
pieces  lake  the  position  shown  on  the  right  side  of  thi- 
figure.  Pack  these  pieces  of  pink  rubber  around  the  neck- 
of  the  teeth  as  shown  mi  the  Lefl   above. 

Cut  strips  of  baseplate  rubber  aboul  's  inch  wide-  and 
pack"  the  diatoric  holes  of  the  posterior  teeth  and  around 
the  pins  of  the  anterior  teeth  until   they  an'  covered. 


Fig.  208. 

Packing  and  Testing,  Paet  II. 

The  balance  of  the  sheet  of  pink  rubber  is  now  folded 
longitudinally  and  cut  lengthwise  into  three  strips  of 
equal  width.  Then  lav  a  strip  of  pink  rubber  of  double 
thickness  against  the  buccal  and  labial  sides  of  the  flask  on 
top  of  the  pink  rubber  already  in  place,  as  shown  above. 
Short  pieces  cut  from  the  end  of  the  strips  of  pink  rubber 
may  be  placed  over  the  lateral  and  cuspid  region  or  wher- 
ever very  bold  contouring  is  to  be  done,  to  give  additional 
thickness. 

Strips  of  base  rubber  of  about  y2  to  %  inches  in  width 
are  now  laid  over  the  palatine  area.  Do  not  place  any 
pieces  of  base  rubber  to  overlie  the  pink  until  the  packing 
has  been  tested. 

To  test,  place  a  thin  piece  of  moistened  percaline  or 
cambric  over  the  hot  soft  rubber ;  place  the  cast  section  on 
the  flask,  put  in  a  small  flask  press  and  very  slowly  and 
cautiously  bring  pressure  to  bear  on  the  flask  contents, 
following  the  yielding  rubber  slowly  with  pressure  so  that 
the  evils  of  rapid  closing  may  be  avoided. 

232 


w 


Fie.  209. 

Packing  and  Testing,  Part  III. 

When  much  pressure  is  needed  to  completely  close  the 
flask  or  when  the  sections  of  the  flask  come  into  contact. 
open  the  flask  and  examine  the  contents  and  either  add 
more  material  or  remove  the  surplus  as  indicated.  Replace 
the  percaline  and  place  in  the  press  and  boil  for  fifteen 
or  twenty  minutes. 

Carefully  close  the  press  until  resistance  is  great  enough 
to  require  strength  to  close  the  sections,  then  open  and 
repeat  the  cutting  away  process  until  the  seel  ions  of  the 
flask  come  almosl  into  perfeel  contact  all  around,  being 
separated  at  most  hv  only  erlough  space  to  accommodate 
the  thickness  of  the  percaline.  Then  finally  close  and 
place  in  the  Donham  clamps  shown  in  the  illustration  on 
the  next    page,  preparatory  to  vulcanizing. 

If  the  test  percaline  slicks  to  the  rubber  a  syringe  full 
.if  ho!  water  squirted  Over  it  till  wet.  will  make  it  easy  i«> 
remove. 


Fig.  210. 

Vulcanizing  and  Opening  the  Flasks. 

The  following  plan  of  vulcanizing  yields  good  results. 
Put  about  four  ounces  of  water  into  the  pot  of  a  A^/o 
three  case  vulcanizer.  Invert  the  flasks  and  the  clamp 
and  place  in  the  vulcanizer  and  close  it.  Adjust  the  tem- 
perature regulator  to  hold  the  temperature  at  270°  or 
280°  F.  Heat  the  vulcanizer  with  the  blow-off  open  till 
steam  escapes,  then  shut  the  blow-off  and  let  the  vulcanizer 
run  for  three-quarters  of  an  hour.  jSTow  move  the  tem- 
perature regulator  to  hold  a  temperature  of  305°  F.  and 
continue  the  vulcanizing  for  one  hour  and  fifty  minutes. 

If  possible  let  the  vulcanizer  cool  slowly.  Do  not  open 
the  blow-off  valve  to  hasten  the  cooling.  If  this  is  neces- 
sary to  hasten  cooling  immerse  the  pot  of  the  vulcanizer 
in  cold  water. 

The  dentures  must  be  carefully  removed  from  the 
flasks  to  prevent  breaking  teeth  or  so  cracking  them  that 
they  will  break  later  in  the  mouth.  Do  not  hammer  the 
flasks.  This  bends  the  flasks  out  of  shape  and  the  shock 
of  the  blows  transmitted  to  the  teeth  may  crack  them. 
Cut  away  the  plaster  on  the  bucco-labial  surface  of  the 
denture  until  the  bottom  of  the  flask  is  reached,  when 
the  denture  may  be  safely  released. 

234 


Fig   211. 

Preparing  Dentures  eor  Polishing,  Part  I. 

A  series  of  casts  of  mouths  exhibil  Lng  bold  festooning  and 
including  the  incisors  and  bicuspids,  will  be  found  to  l>e  of 
greal  assistance  in  imitating  natural  festooning. 

The  festooning  of  the  vulcanite  should  be  much  holder 
than  the  finished  result  expected  as  the  contour  will  be 
much  softened  in  polishing. 

With  the  tile  remove  the  surplus  vulcanite  al  the  mar- 
gins of  the  denture  after  brushing  away  the  plaster  which 
adheres  to  the  denture  with  a  three  row  stiff  bristle  brush. 
The  beveled  chisels  are/nexl  used  tocarve  away  the  vulcanite 
to  the  desired  gingival  outline,  on  both  the  bucco-labial 
and  lingual  surfaces,  cutting  at  right  angles  to  the  tooth. 
Vulcanite  burs  are  then  used  in  a  hand  piece  to  carve 
the  rubber  to  the  required  contour.  By  using  tin4  bur 
with  light  pressure  and  a  drawing  motion  as  it  cuts,  the 
carved  surface  will  be  lefl   smooth  enough  to  polish.     A 

new  sharp  bur  is  hest  adapted  to  rapid  Cutting  and  one 
that  is  worn  is  hest  suited  to  finishing.  Small  depres- 
sions, that  the  large  bur  will  not  reach,  may  be  carved  with 
a  large  rose  bur.  The  interproximal  spaces  are  freed,  from 
the  tins  of  rubber  which  project  between  the  teeth  with 
the  needle-pointed  bur  revolving  rapidly  in  the  hand  piece. 

335 


Fig.  212. 

Preparing  Dentures  for  Polishing, 
Part  II. 

With  the  square  and  beveled  chisels,  round  the  edges  of 
the  gingival  festoons  which  were  left  square.  If  the  lingual 
contour  of  the  natural  teeth  is  to  be  reproduced  in  the  vul- 
canite these  surfaces  should  be  carved  to  the  proper  shape 
with  the  chisels  which  should  be  very  sharp.  Finally,  go 
over  the  curved  surfaces  with  chisels  and  make  these  sur- 
faces so  smooth  that  they  will  require  only  brushing  with 
pumice  to  be  ready  for  the  final  polish. 

The  flanges  of  the  dentures  should  be  carved  to  a  round 
or  cylindrical  contour  and  not  left  sharp  or  very  thin. 

All  small  nodules  or  projections  on  the  inside  of  the 
dentures  should  be  removed  with  a  small  Kingsley  scraper 
but  this  surface  should  be  only  cleaned  with  a  brush  and 
not  polished. 


236 


Polishing 

Mix  one  pari  of  einer)  powder  with  from  six  to  ten 
parts  of  pumice  and  place  the  whole  id  a  shallow  pan 
with  sufHcienl  water  to  render  the  mixture  quite  fluid. 
Place  a  single-row  stiff  bristle  brush  on  the  lathe  spindle, 
and,  starting  with  the  gingival  festoons,  finish  these  to  a 
surface  smooth  enough  to  polish;  follow  this  by  finishing 
the  lingual  surfaces  oi  the  anterior  teeth. 

In  reaching  into  the  fine  depressions  al  the  gingiva]  of 
the  buccal  surfaces  and  on  the  lingual  of  the  upper 
teeth,  the  denture  may  he  held  so  that  the  bristles  of  the 
revolving  brush  will  strike  the  tooth  and  glance  from  it  to 
the  surface  to  be  polished  travelling  in  the  direction  of  the 
depression  to  he  finished.  Do  not  allow  the  bristles  to  run 
long  enough  in  one  place  to  cut  a  channel.  Xcxt  finish 
the  lingual  interproximal  spaces  hetween  the  bicuspids  and 
molars,  and  then  the  main  portions  of  the  buccal  and 
lingual  surfaces,  using  the  rag  wheel  and  a  small  fell  cone 
to  reach  places  that  the  rag  wheel  will  not  touch. 

A  rotary  motion  should  he  imparted  to  the  denture 
when  it  is  being  dressed  on  the  rag  wheel  and  plenty  of  the 
pumice  mixture  should  be  used  to  keep  the  denture  wet. 
Tf  roughness  is  detected, in  the  interdental  spaces  a  sharp 
chisel  should  he  used  to  plane  these  rough  places  smooth 
preparatory  to  a  second  dressing  with  the  bristle  wheel. 

For  the  glossing,  place  the  flannel  wheel  on  the  lathe 
and  hold  a  cake  of  Sure  Shine  against  it  for  a  second  or 
two,  then  hold  the  denture  in  light  contact  with  the  wheel 
while  it  revokes  vapidly,  alternately  pressing  the  denture 
into  the  surface  of  the  wheel  and  withdrawing  it  while 
at  the  same  time  working  hands  in  a  rotary  direction. 

The  dentures  should  he  coated  with  vaseline  or  kepi  in 
water  till  ready  for  inserting  in  the  mouth.  This  mini- 
mizes danger  of  warping. 


Testing  Occlusion  for  Rocking. 

Hold  the  upper  and  lower  dentures  in  occlusion  and  test 
them  to  see  whether  the  change  in  vulcanizing  has  been 
sufficient  to  cause  the  lower  to  rock  on  the  upper.  The 
dentures  are  held  in  occlusion  with  pressure  applied  alter- 
nately in  the  cuspid  and  molar  regions.  Locate  and  cor- 
rect the  points  of  improper  contact.  Cautiously  grind 
these  points  with  a  small  inverted  cone  carborundum  stone. 

The  inclined  planes  of  the  buccal  cusps  of  the  lower 
bicuspids  will  usually  be  found  to  hit  the  inclined  planes 
of  the  lingual  cusps  of  the  upper  bicuspids  too  heavily. 
When  this  occurs  grind  both  of  the  offending  cusps  slightly 
in  such  way  that  the  bite  will  be  deepened  and  not  made 
more  shallow. 

Examine  the  lower  denture  and  cut  away  all  projecting 
portions  of  rubber  which  fit  into  undercuts  in  the  contour 
of  the  lower  ridge.  If  these  projections  are  not  removed 
from  the  denture  they  will  prevent  the  lower  jaw  from 
taking  the  correct  bite  relation.  When  the  lower  denture 
has  been  well  prepared  to  receive  a  wafer  of  compound  it 
will  flare  like  a  V  with  no  projecting  portions  to  interfere 
with  the  smooth,  even  slope  of  the  sides. 


238 


Refitting  the  Lowek  Denture,  Part  I. 

Take  a  cast  of  an  average  size  lower  jaw  that  has  a 
fairly  high  medium  thin  ridge  and  mould  over  it  a  wafer 
of  Perfection  compound  which  has  been  softened  in  water 
at  115°  to  118°  F.  Do  not  thin  the  wafer  in  moulding. 
Trim  away  the  surplus  material  till  only  a  little  more 
than  is  needed  to  cover  the  under  surface  of  the  denture 
remains. 

Warm  the  Wank  and  with  bibulous  paper  or  absorbent 
cotton  moistened  in  the  hot  water,  press  the  blank  against 
the  flanges  of  the  denture  and  adapt  the  compound  well 
to  the  contour  of  the  denture  as  at  "A".  Trim  away  the 
surplus  material  at  the  margins  with  a  sharp  knife  as  at 
••|!".  Chill  the  blank  in  cold  water  and  remove  it  from 
the  denture.  Dry  the  denture  and  the  blank  thoroughly. 
Place  the  dried  blank  in  the  dried  denture  and  seal  the 
margins  of  the  compound  to  the  denture  with  a  hot  wax 
spatula,  pulling  the  soft  compound  toward  the  margins 
of  the  flanges  in  the  operation  as  at  "C".  The  entire 
margin  of  the  compound  must  be  thoroughly  sealed  to  the 
denture  so  that  moisture  cannot  penetrate  between  the 
denture  and  the  compound  and  interfere  with  the  com- 
pound  adhering  to   the   rubber. 

This  part  of  the  technic  may  be  finished  in  the  labora- 
tory. 


239 


Fig.  21  "j. 


240 


Refitting  the  Loweb  Denture,  Part  II. 

h  Is  Importanl  to  the  success  of  the  work  thai  the  po- 
sitions ol  the  fingers  shown  in  the  illustrations  on  the 
opposite  page  be  closely  imitated.  Ii  is  importanl  also  to 
practice  the  following  steps  with  the  lined  denture  cold. 

Place  the  upper  denture  in  the  mouth.  With  :i  si  ick 
of  cocoa  butter  grease  the  palm  side  of  the  join!  of  the 
lirst  finger  of  the  right  hand.  The  water  in  the  heater 
should  be  maintained  nt  a  temperature  of  150°  b\  With 
n  water  syringe  thai  has  a.  l/l(i  inch  opening,  or  a  hoi 
pouring  cup,  direct  a  stream  of  the  hoi  water  upon  the 
compound  of  the  lower  denture  so  thai  the  deeper  por- 
tions of  the  impression  will  receive  the  most  hear.  The 
margins  of  the  flanges  should  he  healed  only  slightly.  ( !on- 
tinue  the  pouring  or  heating  for  about  six  seconds  or  for 
a  sufficient  length  of  time  to  soften  the  compound  slightly. 
Grasp  the  denture  between  the  thumb  and  first  finger 
with  the  ridge  surface  facing'  the  palm  of  the  hand. 

Place  the  lower  teeth  in  the  correct  occlusal  relation 
to  the  upper  and  hold  in  this  position  while  the  thumb 
and  forefinger  of  the  left  hand  are  placed  in  contact 
with  the  buccal  flange  of  the  lower  in  the  bicuspid  region 
in  such  a  manner  that  the  lower  will  he  held  firmly  in 
contact  with  the  upper  denture. 

When  the  left  hand  is  placed  so  that  the  lower  denture 
is  securely  held  against  the  upper,  release  the  thumb 
of  the  right  hand  from  contact  with  the  lower  and  turn 
the  right  hand  palm  down.  The  index  finger  of  the 
right  hand  is  now  used  to  pull  the  Ii])  outside  of  the 
thumb  and  firsl  finger  of  the  left  hand,  so  that  the  lip 
will  not  Interfere  with  the  smooth  closing  of  the  lower 
jaw  that  is  necessary  if  the  bite  is  to  ho  taken  correctly. 
(If  the  margins  of  the  compound  have  been  healed  too 
much  there  is  danger  of  tearing  them  loose  from  the  den- 
ture af   ihis  l  ime.) 

Xow  direct  the  patient   to  place  the  tip  ol'  the  tongue 

241 


Refitting  the   Lower  Denture 
(Part  II,  Continued). 

against  the  rear  portion  of  the  upper  vault  and  slowly 
close  the  lower  jaw  till  the  ridge  makes  an  imprint  in  the 
soft  compound  on  the  bottom  of  the  lower  denture.  As 
the  ridge  of  the  jaw  approaches  the  point  where  it  touches 
the  compound  it  will  press  against  the  thumb  and  finger 
which  hold  the  lower  denture  against  the  upper  at  the 
point  where  they  extend  slightly  under  it.  Allow  the  up- 
ward pressure  of  the  ridge  to  force  the  fingers  and  thumb 
upward  while  they  still  maintain  a  firm  pressure  on  the 
denture  to  keep  it  seated  against  the  upper. 

When  the  mouth  has  been  closed  the  fingers  should  be 
removed  and  the  patient  instructed  to  suck  while  con- 
tinuing the  biting  process.  Chill  the  compound  with  cold 
water  and  remove  the  denture  from  the  mouth.  Chill  it 
thoroughly  by  immersing  in  cold  water,  then  place  in  the 
mouth  and  examine  to  see  whether  the  cuspids  strike  in 
occlusion  as  they  did  when  the  preliminary  examination 
for  occlusion  was  made.  If  more  space  is  found  between 
the  upper  and  lower  cuspids  than  should  be  this  indicates 
an  error,  to  correct  which,  heat  the  compound  on  the 
under  side  of  the  denture  and  repeat  the  technic  to  this 
point.  It  is  sometimes  necessary  to  add  a  new'  blank  of 
compound  to  the  under  side  of  the  lower  and  repeat  the 
entire  technic. 

When  the  lower  is  properly  seated  on  the  ridge  so 
that  the  patient  can  open  the  mouth  and  snap  the  lower 
teeth  quickly  against  the  upper,  producing  a  sharp,  clear 
noise,  and  when  a  close  examination  reveals  no  defect  in 
the  occlusion  or  articulation  such  as  would  be  due  to  seat- 
ing the  lower  incorrectly  against  the  upper,  the  fit  may 
be  still  further  improved  by  heating  the  compound  with 
a  hot  water  stream,  which  should  lie  allowed  to  touch  only 
the  deep  portions  of  the  compound  made  by  the  ridge, 
for  about  eight  seconds,  then   placing  the  lower  in   the 

24a 


Refitting  the   Loweh    Denture 
(  Pari    I  [,  Continued). 

mouth  tin  the  ridge,  requesting  the  patient  to  close  with 
the  tongue  touching  the  roof  of  the  mouth,  exert  biting 
pressure,    and    suck. 

Chill  the  compound  to  a  stage  in  which  if  will  nol 
change  its  form  and  remove  from  the  mouth  and  complete 
the  chilling  in  cold  water. 

With  a  tracing  stick  make  additions  to  the  flanges  of 
the  compound  in  the  areas  over  the  location  of  the  pro- 
jections of  vulcanite  that  were  cut  away  at  the  beginning 
of  the  operation.  At  these  points  the  single  thickness  of 
the  compound  wafer  requires  reinforcing  to  provide 
enough  material  to  take  a  correct  impression  of  the  tissues. 
Chill  the  added  compound  and  proceed  as  directed  in  the 
technic  described  for  the  use  of  the  tracing  stick  on  page 
3  49,  instructing  the  patient  to  suck. 

The  lower  denture  should  he  perfectly  stable  on  the 
ridge  and  exhibit  marked  suction.  If  it  has  stability  and 
no  suction,  press  one  side  against  the  ridge  with  the 
fingers  of  one  hand  which  are  supported  by  pressure  of 
the  thumb  on  the  lower  border  of  the  mandible,  and  grad- 
ually lower  the  other  side  till  seated  on  the  ridge,  watch- 
ing for  appearance  of  bubbles.  Repeat  this  several  times 
and  watch  closely  for  the  appearance  of  bubbles  which 
will  be  formed  in  the  region  where  air  escapes  at  the 
point  of  imperfect  adaptation.  Corred  the  adaptation  by 
adding  compound  from  a  tracing  stick,  as  described  in  a 
previous  paragraph.  Imperfect  adaptation  which  inter- 
feres with  suction  is  most  likely  to  occur  at  the  heels  of 
the  denture  and  at   the  I'reiium  linguae. 


843 


Refitting  the  Lowek  Denture,  Part  III. 

It  frequently  happens  that  the. lower  denture  is  not 
made  long  enough  to  secure  stability  and  suction.  To 
correct  this  condition  trace  a  bulk  of  soft  compound  on 
the  upper  side  of  the  heel  of  the  denture  as  shown  at  the 
top  of  the  page.  Place  the  denture  in  the  mouth,  the  upper 
being  in  place,  and  have  the  patient  close  and  suck.  If 
the  surface  of  this  addition  is  not  smooth  enough,  correct 
the  defects  by  the  use  of  the  tracing  stick. 

The  edges  of  the  compound  addition  should  be  trimmed 
so  that  the  margins  of  the  flanges  will  be  well  rounded. 
The  flanges  should  not  be  allowed  to  extend  below  the  ex- 
ternal oblique  line  on  the  buccal  side  nor  below  the  mylo- 
hyoid line  on  the  lingual  side.  Place  the  lower  denture 
against  the  upper  in  occlusion  and  make  sure  that  the 
compound  additions  do  not  strike  the  upper  so  as  to  inter- 
fere with  lateral  motions  of  the  jaw. 


244 


Refitting  the  Lower  Dextuke,  Part  IV. 


Scrape  away  the  compound  which  has  been  forced 
upward  on  the  buccal  and  lingual  flanges  of  the  lower. 
Make  a  very  stiff  mixture  of  equal  parts  of  Spence  plaster 
and  plaster  of  Paris  and  till  the  cup  portion  of  a  flask. 
Work  some  of  this  stiff  mixture  into  the  interproximal 
spaces  and  the  occlusal  surfaces  of  the  teeth.  With  gentle 
rotating  pressure  force  the  denture  into  the  plaster  in  the 
flask,  i  ill  the  edge  of  the  bucco-labial  flange  is  at  the  level 
of  the  edge  of  the  flask.  The  denture  should  be  placed 
well  forward  in  the  flask  to  provide  ample  room  to  prepare 
a  Hat  sloping  surface  back  of  the  heel  to  facilitate  parting 
for  packing.  Smooth  the  plaster  as  shown  in  the  illustra- 
tion and  trim  it  to  the  point  where  the  compound  joins  the 
rubber  excepl  ni  the  heel  where  ibis  is  impossible.  When 
the  plaster  bus  hardened,  coat  it  with  ibin  sandarac  var- 
nish and  lay  on  the  plaster  a  strip  of  wax  as  shown,  aboul 
Wo  inch   away  from   the  compound. 


Fig.  21 S. 

Refitting  the  Lower  Denture,  Part  V. 

Seal  the  ring  of  the  flask  firmly  and  evenly  upon  the 
poured  cup  section.  Make  a  mixture  of  pure  Spence 
plaster  or  of  half  Spence  and  half  plaster  of  Paris,  free 
it  from  bubbles  as  described  on  page  158  and  distribute  it 
over  the  impression  in  the  manner  used  in  making  the 
casts.  Fill  the  ring  to  the  top  and  place  the  lid  on  it 
and  set  a  weight  on  the  lid  or  clamp  the  flask  lightly  in 
a  clamp  or  press.  Allow  the  plaster  to  set  thoroughly  and 
heat  the  flask  before  opening  for  about  fifteen  minutes  in 
water  at  about  118°  F.  If  the  flask  is  overheated,  the 
compound  will  adhere  very  tenaciously  to  the  rubber. 

Refitting  the  Lower  Denture,  Part  VI. 

The  rubber  which  replaces  the  compound  should  be 
thick  enough  to  vulcanize  properly  but  only  as  much 
thicker  than  this  as  conditions  make  absolutely  necessary. 
At  the  places  where  the  compound  was  very  thin  cut  away 
enough  vulcanite  with  an  oval  vulcanite  bur  to  provide 

246 


Refitting  the  Lower  Denture,  Continued. 

space  for  a  bulk  of  rubber  one-half  nun.  thick.  With  the 
same  bur  freshen  the  cut  ire  surface  of  exposed  vulcanite. 
The  cduvs  of  the  flanges  may  be  squared  with  a  carborun- 
dum stone.  Cut  grooves  with  a  wheel  bur  as  shown  in 
the  illustration,  one  o\'  which  extends  entirely  around  the 
periphery  of  the  denture  about  1/16  of  an  inch  away  from 
the  edge,  the  others  diagonally  across  the  surface  of  it. 

Warm  the  flask  slowly  over  an  electric  heater  or  a  slow 
gas  flame  till  the  vulcanite  is  hot  enough  to  be  uncom- 
fortable to  touch,  then  lay  on  it  a  series  of  strips  of  rubber 
about  one-qnarter  inch  wide,  till  the  surface  is  covered. 
Tt  is  better  to  have  a  surplus  of  rubber  than  not  enough  to 
insure  the  forcing  of  the  softened  rubber  into  the  grooves 
when  the  test  closure  is  made.  Coat  the  cast  and  the 
adjacent  plaster  of  the  reverse  half  of  the  flask  with  Silex, 
allow  to  stand  for  a  minute,  then  wash  away  the  sur- 
plus Silex  under  the  water  faucet.  Place  percaline  be- 
tween the  sections  of  the  flask  and  put  them  together  in  a 
flask-press,  exerting  very  slight  sustained  pressure  so  as 
to  follow  the  rubber  as  it  flov^s.  When  further  closing 
with  very  light  pressure  is  impossible,  open  the  flask  and 
cut  away  the  surplus  rubber  which  has  flowed  over  the 
retaining  wall,  replace  the  percaline  and  close  the  flask 
till  resistance  to  pressure  is  felt.  Boil  the  flask  for  fifteen 
minutes  or  more  and  apply  closing  pressure  to  the  press. 
Much  better  results  are  obtained  by  using  sufficient  heat 
and,  opening  the  flasks  three  or  four  times,  if  necessary, 
to  remove  surplus  rubber  than  by  attempting  to  force  in- 
sufficiently heated  rubber  to  How.  When  the  metal  edges 
of  the  flask  sections  come  together,  remove  the  percaline 
and  surplus  rubber,  place  in  a  Donham  clamp  and  vul- 
canize, holding  the  temperature  at  270°  F.  three-quarters 

of  an  hour,  then  raise  it  to  -'Jl'O0  F.  and  hold  here  for 
tiftv-tivo  minutes. 


•:  i  ;■ 


Fitting  the  Dentures  to  the  Mouth  and 
Perfecting  the  Articulation. 

When  the  upper  and  lower  dentures  are  in  place  in  the 
mouth,  the  occlusal  surfaces  of  the  teeth  should  permit  of 
easy,  free  lateral  and  protrusive  movements  of  the  man- 
dible. A  slight  unavoidable  shifting  of  the  teeth  occurs 
in  vulcanizing  and  this  interferes  with  the  occlusal  sur- 
faces of  the  two  sets  gliding  as  freely  on  one  another  in 
the  mouth  as  they  did  in  the  articulator.  It  has  com- 
monly been  supposed  that  grinding  in  the  articulator 
would  accomplish  the  change  necessary  to  establish  accu- 
rate smooth  working  of  the  teeth  in  mastication.  While 
this  is  true  to  a  degree  it  must  be  remembered  that  there 
is  always  present  in  natural  dentures  a  certain  freedom  or 
latitude  of  movement  which  permits  the  teeth  to  slide 
freely  without  engaging  accurately  in  a  definite  restricted 
way. 

This  latitude  of  movement  is  due  to  a  very  slight  yield- 
ing of  the  inter-articular  tissues  of  the  temporo  mandib- 
ular articulation  and  also  to  some  extent  to  a  yielding  of 
individual  teeth  in  their  sockets  and  to  a  variation  in 
muscular  tension  which  cannot  be  duplicated  in  a  metal 
articulator. 

It  seems  natural  to  suppose  that  the  most  rational  place 
to  secure  the  final  adjustment  of  the  dentures  to  each 
other  would  be  in  the  mouth.  Following  this  plan  the  lati- 
tude of  movement  peculiar  to  the  patient  may  be  used  to 
produce  a  free  movement  in  the  articulation  of  the  den- 
tures, which  will  permit  the  patient  to  use  the  habit- 
ual movements  in  masticating  with  comfort  and  efficiency. 

While  grinding  the  teeth  in  the  mouth  the  dentures 
are  supported  on  their  respective  ridges  and  the  patient 
directed  to  work  the  jaw  in  lateral  and  protrusive  move- 
ments with  a  suitable  abrasive  between  the  occlusal  sur- 
faces of  the  teeth. 


248 


Fig.  mo. 

Fitting  the  Dentures  to  the  Mouth  and 
Perfecting  the  Articulation — Cont. 

Before  commencing  to  grind  the  teeth  in  the  mouth, 
correct  visible  errors  in  articulation  by  grinding,  where 
necessary,  with  a  carborundum  stone,  observing  the  fol- 
lowing  points : 

When  the  lower  is  protruded,  so  that  the  median  line 
above  is  directlv  over  the  median  line  below  and  the  in- 
cisors hit  end  on,  the  dentures  should  be  balanced  on  the 
centrals  in  front;  the  upper  cuspid  should  touch  the  lower 
first  bicuspid;  the  second  upper  bicuspids  should  resl  on 
the  lower  first  molars  or  the  mesial  cusps  of  the  upper 
first  molar  should  rest  on  the  lower  firsl  molars  to  balance 
and  support  the  dentures  in  the  rear.  Other  supports  may 
exist  bul  no  heavy  pressure  should  be  permitted  to  come 
on  the  lower  second  molar.  The  mesial  cusp  of  the  lower 
cuspid  should  not  touch  the  upper  lateral  in  this  or  any 
other  relation  of  the  dentures. 

When  it  is  necessary  to  shorten  the  lower  incisors  to 
let  the  upper  cuspids  touch  the  lower  firsl  bicuspids,  -rind 
away  the  lingual  surfaces  and  nol  the  labial.     The  tips  of 

249 


Fitting  the  Dentures  to  the  Mouth  and 
Perfecting  the  Articulation — Cont. 

the  cusps  of  other  interfering  teeth  may  also  be  ground 
where  necessary  to  establish  proper  supporting  contacts 
without  decreasing  danger  of  the  efficiency  of  the  dentures. 

Try  the  dentures  in  right,  and  left  lateral  articulation 
and  correct  the  contacts  of  any  teeth  that  prevent  proper 
relations  of  adjoining  teeth  in  both  the  working  and  bal- 
ancing bite  for  both  sides  of  the  denture. 

When  this  has  been  accomplished  mix  one  part  of  a 
cocoa  butter  such  as  is  sold  for  coating  synthetic  fillings, 
with  about  four  parts  by  volume  of  Copper  Carbo  powder. 
The  mixing  can  be  best  done  on  a  glass  slab  with  a  hot 
cement  spatula.  Dry  the  teeth  of  both  dentures  and  smear 
the  lingual  surfaces  of  the  upper  incisors  and  the  occlusal 
surfaces  of  the  lower  posteriors  with  the  abrasive  mix- 
ture. Place  the  dentures  on  the  ridges  and  hold  them 
there,  while  the  patient  moves  the  lower  from  right  to 
left,  keeping  it  in  the  retrnded  position. 

At  first  it  will  be  noted  that  the  lateral  movement  tends 

250 


Fig.  221. 

Fitting  the  Dentures  to  the  Mouth  and 

Perfecting  the  Articulation — Cont. 

to  cause  the  dentures  to  rotate:  however,  this  tendency 
decreases  as  the  grinding  progresses. 

It  is  not  sufficient  to  let  the  patient  chew  the  abrasive. 
The  dentures  must  be  firmly  supported  on  their  ridges 
till  all  tendency  to  rotate  disappears. 

Follow  the  grinding  from  side  to  side  with  grinding 
for  the  fronl  to  back  movements  of  the  jaw. 

Allowing  for  occasional  short  rests  for  the  patient  if 
aged,  this  operation  should  consume  from  twenty  minutes 
to  one-half  hour.  It  is  of  course  impossible  to  use  this 
method  effectively  on  plain  line  dentures  or  teeth  that  are 
no1  anatomically  correct  in  design — as  the  amount  of 
grinding  necessary  under  these  conditions  will  render  im- 
possible anything  like  fair  results. 

The  grinding  should  be  continued  only  until  the  den- 
tures work  smoothly. 

Smooth  off  sharp  edges  on  the  incisal  of  the  anteriors 
with  sandpaper  disks,  treal  the  cusp  edges  in  the  same 
manner  and  the  operation  is  complete. 


.•••i 


Fig.  222. 


Finis 


The  teclmic  described  in  the  foregoing  pages  produces 
artificial  dentures  which  are  natural  in  appearance,  com- 
fortable in  use,  stable  in  all  positions  of  the  jaw  and  effi- 
cient in  mastication. 

Such  denture  service,  and  only  such  denture  service 
when  it  can  be  rendered,  discharges  the  obligations  which 
are  placed  upon  us  by  our  professional  position,  by  the 
dependence  of  edentulous  patients  upon  our  knowledge 
and  skill,  by  the  economic  worth  of  many  edentulous  per- 
sons and  by  their  right  to  life,  health  and  the  pursuit  of 
happiness. 

For  this  reason  we  have  called  service  of  this  quality 

PROFESSIONAL  DENTURE  SERVICE. 


250 


Index 


PART 


Impressions  and  Bn  es 


page 

Attaching   the    Impression   Compound    ■"'! 

Attaching   the  Lower  Bite  Rim    62 

Attn. •hin-  the   Upper  Bite  Rim— Part  I     44 

Attaching  the   Upper   Bite   Kim      Part   II     45 

Attaching   the   Upper   Bite  Rim-  -Part   III     .    4C 

Carrying  the  Bite  Rimmed  Lower  Tray  Into  the  Mouth 63 

Carrying  the  Compound  Flanges   High    39,    i" 

Chilling  the  Compound   Next    to   Tray 33 

Chilling  the  Right-hand   Marginal    Flange 35 

Classification  of  Tissue  Conditions  in  Edentulous  Mouths ....  16-19 

Completing  the   Upper  Bite  Rim 54 

Compound-Plaster  Impressions   95 

Correcting  Errors  in  Rite  Rim  Depth — Part   I    '<- 

Correcting  Errors  in   Bite  Rim  Depth — Part   II    53 

Determining  Length  of  Trav   -I 

Establishing  the   Plane  of  Occlusion — Part   I     4s 

Establishing  the   Piano  of  Occlusion — Part   II    4!> 

Equalizing   Surface  Temperature  of   Compound 36 

Forming  the  Lower  Bite  Kim 61 

Guide   Rimming  the  Lower  Tray .iT 

Heater  for  Impression  Compound    23 

Heating  the  Upper  Buccal  Flange  for  Muscle  Trimming T'.i 

Heights   of  the    Bite   Rims 89-9] 

Impression    Marked   for   Relief 86 

Inserting  the  Lower  Tray 58 

Inserting  the  Tray  for  the  Lower  Impression ii7 

Introducing  Compound  for   Upper   Impression — Part   I     31 

Introducing  Compound  for   Upper   Impression — Pari    II      38 

Locating  Compressible   Palatal   Tissues    20 

Lower    Trays    55 

Merits    of    Compound    Impressions    14 

Muscle  Trimming  the  Lower  Lingual   Flange — Part    I    7  1 

Muscle   Trimming  the   Lower   Lingual    Flange— Pari    II     ~'< 

Muscle  Trimming  i  he   Labial   Flange  of   the   Upper   Impression 

Part   I 81 

Muscle  Trimming  the   Labial    Flange  of   the   Upper   Impression 

Part   II    *L> 

Muscle   Trimming  die  Upper   Buccal    Flanges 80 

Outlining  Areas  for  Compression  and  Relief 83 

Perfecting  Adaptation  of  the  Upper  Flange  to  the  Ridge vv 

Perfecting  Hie   l "i i    of  the  Trav      Part   I     'J  I 

Perfecting  the  Lit  of  the  Trav — Part  II     25 

Perfecting  the   Lit   of  the  Tray — Tart  III    26,  27 

Placing  tin'  P.ite   Rimmed  Lower  Tray....*. til 

Plaster   Upper  Compound   Lower 96 

Preparing  the  Upper  Tray  for  the  Attachment  of  '!"■  Compound  28 
Preparing  the  Upper  Tray  for  the  Attachmenl   of  the   Lite  Rim. 29 

Relief  Over  the  Course  of  the  Palatine  Artery 84 

Restoring  facial   Expression— Part  I     92 

Restoring  facial   Expression— Pari    II    93 

Restoring   Facial   Expression— Part   III    :'i 

Seating    the    Lower    Tray 59,    Co 

Shaping   the  Compound   for  the  Lower   Impression 66 

Shaping    t  he  Compound   in   I  he  Tray    32 

Shaping  the  Lower   Tray    56 


INDEX— Continued. 
Impressions  and  Bites — Continued 

TAGE 

Softening  Palatal   Surface   of  Compound 34 

Stabilizing  the  Lower   Impression 78 

Teclmic  for   Heating  Flange  for  Muscle  Trimming 71 

Test    for    Quantity     30 

The  Plane  of  Occlusion — Front    View    50 

The  Plane  of  Occlusion — Side  View 51 

The   Incomplete    Lower    Impression 69 

The  Relation  of  the  Lower  to  the  Ridge 77 

Transferring   Markings    to    Impression 85  . 

Trimming  the   Buccal   Flange    70 

Trimming  the   Impression  for   Length 42,   43 

Trimming  the  Lower   Rite    Itim.  . ; 65 

Trimming  the  Lower  Buccal  Flange 73 

Trimming  Lower  Labial  Flange — Cuspid  to  Cuspid 72 

Trimming  the  Surplus  from  the    Lower    Impression 70 

Trimming  the   Surplus  from  Upper    Impression 41 

Trimming  the  Upper   Impression  at  the  Frenum 87 

Trimming   Upper    Impression    Trays    22 

Turning   Up   the    Surplus    Compound   on   Buccal   and   Labial    Sur- 
faces  68 

What  the  Occlusal  Plane  Is 47 


PART  II 

Selecting  the  Size,  Form  and  Shade  in  Artuucial  Teeth 

Determining  the   Type  of   Face    113 

Dimensions  Trubyte  Moulds — Uppers    114 

Dimensions  Trubyte  Moulds — Lowers    115 

Harmony  of  Form  in  Faces  and  Teeth 102-105 

Locating  the  Distal    Sides   of   the   Cuspids    99. 

Marking  the  Median  Line    98 

Measuring  for  Width  of  Upper  Anteriors    101 

Shading  in  Artificial  Teeth    119 

Suggestions  for  the  Selection  of  Shades   121 

Surface  Texture  and  Tooth  Shades   123 

Table  of  Colors  in  the  Twentieth  Century  Shade  Guide 122 

Trubyte  Selection  Rim 118 

Trubyte  Teeth— Mould  Guide    110 

Typal  Forms   in  Natural  Teeth    • 112 

Typal  Ovoid     Face     110 

Tvpal   Square   Faces    100 

Tvpal  Tapering   Faces    108 

Use  of  a  Mould  Guide   .  ,  , , 117 


PART  III 

Measuring  Habitual  Masticating  Movements 

Adapting  Baseplate 175-177 

Adjusting  the  Condyle   Path    Register   and   Removal 148 

Adjusting  the  Horizontal   Pencils    134 

Adjusting  the  Vertical  Pencils   143 

Attaching  the  Horseshoe  Plate  to  the  Bite  Rim    132 

Attaching  the  Incisor    Path    Marker    to    the    Impression    137 

Blackening  the  Horseshoe   Plate    138 

Building  the  Lower  Bite  Rim  Forward 180 

Condyle  Path  Register  and  Accessories    127 

254 


INDIA     Continued. 
Measuring   M  \ r. i  i  i  \ i.  Masticating   Movements     Continued 

iw.i: 

Correct   and   Incorrect    Descending    Inclination    Record    130 

Correct   and   Incorrect    Incisor    Path    Records    140 

Correcl   and    Incorrect    Lateral     Baths     i  it 

Correcting    Lack    of    Fit    in    the    Impressions    149,    150 

Determining  the  Depth  of  Relief   15:! 

Drawing  Base  Lines  Cor  the  Lateral    Inclination   Records   Ill" 

Equalizing   Biting  Strain   on   the   Bite   Kims    i:::: 

Holding- the   Lateral    Path   Register-    Bart    l    in 

Holding  the   Lateral    Bath   Register     Bart    II    14." 

Interferences  thai   Brevenl  Correct   Records  120 

Locating  the   Heads  of  the  Condyles 12!) 

Locating  the   Horseshoe    Blate    130 

Locating  the   Rotation   Poinis— pari    i     171 

Locating  the.   Rotation   J'oinis     Bail    If    1  tu 

Locking  Hi''   Bites   152 

Locking   the    Bite   Kims    fur   Mounting    165 

Making  ('.-ists     Bart    I     159 

Making   Casts — Bart    II    ICO 

Marking  Lines  on  the   Upper  Cast   IT.'! 

Mixing   (In'   Material    for   Casts    158 

Mounting  Casts  on  the  Adaptable  Articulator   1G7-170 

Preparing  the  Bite  for  Locking  153 

Preparing  the  Impressions   for  Making  Casts — Part   I    155 

Preparing  the   Impressions  for  Making  Casts — Part    II    1~><; 

Protecting  the  Bite  Kims  ami  Records  During  Casting 157 

Recording   the   Lateral    Inclination    in; 

Re-Forming  the  Lower  Bite  Rim     178 

Re-Forming  the  Upper  Bite  Kim .  ,  i  s i 

Registering  the  Descending  Inclination  of  the  Condyle  Path.... 135 

Relieving   the   Impression    1'54 

Removing  the  Cower  Impression  from  the  Cast 174 

Removing  and   Replacing   the   Upper    Bart  of  tin'   Adaptable  and 

Simplex   Articulators    182 

Reproducing  the  Descending  Inclination  of  the  Condyle  Path — 

Part  I   .' 161 

Reproducing  the   Descending  Inclination   of  the   Condyle   Bath — 

Part   II    .' 162 

Reproducing    the    Lateral    Inclination    of    the    Condvle    Path — 

Part  I    ' 163 

Reproducing    the    Lateral     Inclination    of    the    Condyle    Path — 

Part   II    164 

Taking  the  Incisor  Path  Record    139 

Trimming  and   Marking   the   Lower    Bite    Rim    1T0 

Why    It    Is   Worth    While   to    Reproduce   .law    .Movements T_>.". 

Withdrawing   the   Condyle    Path   Register    131 


I"  \UT  IV 


Arranging  the  Teeth 


Arranging  the  Teeth     1S4 

Arranging  the   Upper  Anteriors    185-188 

Arranging  the  Upper  Posteriors     189-192 

Arranging  the  Teeth-  The  Lower  First  Molar   196  199 

Arranging  the  Teeth — The  Bicuspids     200  202 

Arranging   the  Teeth— The  Cuspids 203-204 

Arranging  the  Teeth — The   Incising   Bite    205-206 

Arranging  the  Teeth — The   Lower  Second  Molars   209,  210 

llow  to  Move  the  Articulator   Properly    195 

Inspecting  the  Trial    Dentures  in   the  Mouth    207,   208 

Working  and  Balancing  Molai   Contacts   194 

355 


INDEX— Continued. 

PART  V 
Simplex  Akticulatok  and  Snow  Face  Bow 

PAGE 

Adjusting  the  Face  Bow  to  the  Face — Part  I    215 

Adjusting  the  Face  Bow  to  the  Face — Part  II    21(5 

Adjusting  the  Face  Bow  to  the  Face— Part  III 21S 

Attaching  the  Horseshoe    Plate 214 

Building    Separate    Bite    Plates    212 

Face  Bow  Technic  for  Large   Cases    224 

Mounting  Casts  on  the  Simplex  Articulator  with  a  Face  Bow — 

Part  I    220 

Mounting  Casts  on  the  Simplex  Articulator  with  a  Face  Bow — 

Part  II 221 

Mounting   Casts   on    the    Simplex    Articulator   without   the    Face 

Bow 222,   223 

Removing  the  Face  Bow    210 

Simplex  Articulator  and  Accessories 212 

Taking  the  Incisor  Path  Record , 217 


PART  VI 

Flasking,  Vulcanizing,  Finishing  and  Perfecting  the  Fit 

Fitting  the   Dentures  to   the   Mouth  and  Perfecting  the  Articu- 
lation     248-251 

Flasking  the  Dentures — Part  I    228 

Flasking  the  Dentures — Part  II     229 

Finis    252 

Packing  and  Testing — Part   I     231 

Packing  and  Testing — Part  II    232 

Packing  and  Testing — Part   III     233 

Polishing    237 

Preparation  of  Channel  for  Waste  Rubber '.  230 

Preparing  Dentures  for  Polishing — Part  I    235 

Preparing  Dentures  for  Polishing — Part    IT    236 

Preparation  of  Trial   Dentures   for   Flasking — Part    I     220 

Preparation  of  Trial  Dentures  for  Flasking — Part   II    227 

Refitting  the  Lower  Denture — Part  I 239 

Refitting  the  Lower  Denture — Part  II    241-243 

Refitting  the   Lower  Denture — Part  III     244 

Refitting  the  Lower  Denture — Part  IV    245 

Refitting  the  Lower  Denture — Part  V    240 

Refitting  the   Lower  Denture — Part  VI     247 

Testing  Occlusion  for  Rocking    238 

Vulcanizing  and   Opening   the   Flasks    , , 234 


256 


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